Which church father first taught the perpetual virginity of Mary? Reformed theologian Herman Bavinck, in his Reformed Dogmatics, III, §366, briefly deals with Mary's perpetual virginity, and touches on the doctrine's history:


  We do not yet find this idea of Mary's continuing virginity during and after the the birth of Jesus in the church fathers before Nicea.  Tertullian, Origen, and Irenaeus do not yet attest a virginity in childbirth, and Tertullian also rejects the virginity after the birth.


Bavinck seems to discount the Protevangelium of James as not being the work of a church father, and for not mentioning Mary's continued virginity after Jesus' birth.  He then goes on to identify a wide variety of post-Nicene authors who teach Mary's virginity both during and after the birth. 

This understanding seems to contradict Wikipedia, which cites a Karl Rahner's 2004 Encyclopedia of theology when it says:


  Irenaeus (c.130 – c.202) taught perpetual virginity, along with other Marian themes.


In light of this disagreement, I'd like to know which church father was first to teach the complete doctrine, that is, the virginity of Mary both during and after the birth of Jesus.  I don't think it will matter, but we can include Tertullian and Origen as church fathers here.  And as always, primary sources will be much appreciated.
As with many doctrines in the first few hundred years of the church, they tended not to be explicitly defined until heretics arose forcing the church to define doctrine. 

This is why history is scarce on people speaking of this doctrine until the Antidicomarites show up in the mid to late 300s.

With that said, here's the records we have:


~100 AD: Ignatius of Antioch
~150 AD: Polycarp (disciple of John the Apostle)
~160 AD: Justin Martyr
~200 AD: Irenaeus


  In the year AD 383, Jerome writes that Ignatius, Polycarp, Justin Martyr, and Irenaeus all “held these same views” of Mary’s perpetual virginity and “wrote volumes replete with wisdom” (in his The Perpetual Virginity of Blessed Mary: Against Helvidius, section 19). 
  No writings from these 4 men survived that unambiguously identifies their belief in this doctrine, but we assume Jerome had access to some of their many works that did not survive until the modern day.

248 AD: Origen


  "Mary, as those declare who with sound mind extol her, had no other son but Jesus" [Origen's Commentary on the Gospel of John (Book I), Section 6]



Then as the Antidicomarites show up, we see an explosion in references to the doctrine (after the council of Nicea in 325 AD, as your source noted):


354 AD: Hilary of Poitiers


  "If they [the brethren of the Lord] had been Mary's sons and not those taken from Joseph's former marriage, she would never have been given over in the moment of the passion [crucifixion] to the apostle John as his mother, the Lord saying to each, 'Woman, behold your son,' and to John, 'Behold your mother' [John 19:26-27], as he bequeathed filial love to a disciple as a consolation to the one desolate" [Hilary's Commentary on Matthew 1:4]

360 AD: Athanasius


  Identifies Mary as "Mary Ever-Virgin" in his Discourse 2 Against the Arians, Section 70

373 AD: Ephrem


  "Because there are those who dare to say that Mary cohabited with Joseph after she bore the Redeemer, we reply, 'How would it have been possible for her who was the home of the indwelling of the Spirit, whom the divine power overshadowed, that she be joined by a mortal being, and gave birth filled with birthpangs, in the image of the primeval curse?'" [Ephrem's Commentary on Tatian's Diatessaron]

~375 AD: Basil of Caesarea


  "...the lovers of Christ do not allow themselves to hear that the Mother of God ceased at a given moment to be a virgin..." [Basil’s Homily: On the holy generation of Christ 5; PG 31, 1468 B]

375 AD: Epiphanius


  "For I have heard from someone that certain persons are venturing to say that [Mary] had marital relations after the Savior’s birth. And I am not surprised. The ignorance of persons who do not know the sacred scriptures well and have not consulted histories, always turn them to one thing after another, and distracts anyone who wants to track down something about the truth out of his own head.” [The Panarion of Epiphanius of Salamis: De fide. Books II and III, page 620, 7.1]

383 AD: Jerome


  In his The Perpetual Virginity of Blessed Mary: Against Helvidius he gives a long, full biblical defense of Mary's perpetual virginity, noted in earlier sections in this answer.

386 AD: Didymus the Blind


  "Mary... remained always and forever an immaculate virgin" [Didymus's The Trinity 3:4]

388 AD: Ambrose of Milan


  Identified prophecy of Ezekiel 44:2 as proof of Mary's perpetual virginity in his De Institutione Virginum 8.52

401 AD: Augustine


  "A Virgin conceiving, a Virgin bearing, a Virgin pregnant, a Virgin bringing forth, a Virgin perpetual. Why do you wonder at this, O man?" [Augustine, Sermons 186:1]



And so on, this wiki continues the belief through to the modern era including the reformers.