Net Gains on Loans Held for Sale (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash loss:
Loans									$ (190,853)	$ (469,647)	$ (174,669)
Hedging activities									(175,305)	93,288	(16,866)
Cash gain (loss), net of effects of cash hedging, on sale of loans held for sale									(366,158)	(376,359)	(191,535)
Non-cash gain:
Mortgage servicing rights and mortgage servicing liabilities resulting from loan sales									846,888	584,156	563,872
Provision for losses relating to representations and warranties on loans sold pursuant to loan sales									(8,377)	(5,824)	(5,890)
Provision for losses relating to representations and warranties on loans sold reduction in liability due to change in estimate									7,877	4,672	4,301
Change in fair value of loans and derivatives held at year end:
Interest rate lock commitments									87,312	(8,934)	(1,120)
Loans									(42,878)	(1,506)	4,576
Hedging derivatives									17,499	(11,766)	(4,389)
From non-affiliates									542,163	184,439	369,815
Net gains on loans held for sale at fair value	$ 257,487	$ 235,732	$ 147,533	$ 84,776	$ 59,748	$ 56,914	$ 60,946	$ 71,414	725,528	249,022	391,804
PMT
Change in fair value of loans and derivatives held at year end:
Recapture payable to PennyMac Mortgage Investment Trust									$ 183,365	$ 64,583	$ 21,989