Related Party Transactions - Financing Activities (Details) - USD ($)	3 Months Ended	6 Months Ended
	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020	Dec. 31, 2020	Feb. 01, 2013
Financing activities:
Issuance pursuant to recapture agreement		$ 557,000	$ 862,000
Repayments		134,624,000	17,430,000
PMT
Financing activities:
Interest expense	$ 2,372,000	1,280,000	4,346,000
Change in fair value	636,000	(1,037,000)	15,158,000
Excess servicing spread financing at fair value payable to affiliate				$ 131,750,000
PMT | 2/1/13 Spread Acquisition Agreement
Financing activities:
Maximum ESS recapture obligation					$ 200,000
Excess servicing spread financing | PMT
Financing activities:
Balance at the beginning of the period	157,109,000	131,750,000	178,586,000
Issuance pursuant to recapture agreement	483,000	557,000	862,000
Interest expense	2,372,000	1,280,000	4,346,000
Repayments	(8,122,000)	(134,624,000)	(17,430,000)
Change in fair value	(636,000)	1,037,000	(15,158,000)
Balance at the end of the period	151,206,000		151,206,000
Excess servicing spread recapture recognized	$ 535,000	$ 614,000	$ 916,000