Related Party Transactions - Amounts due from Affiliate (Details) - PMT - USD ($) $ in Thousands	Jun. 30, 2021	Dec. 31, 2020
Amounts due from affiliate
Allocated expenses	$ 17,002	$ 38,142
Fulfillment fees	16,467	20,873
Management fees	11,913	8,686
Correspondent production fees	9,764	13,065
Servicing fees	6,737	6,213
Interest on assets purchased under agreements to resell		26
Total due from affiliate	61,883	87,005
Payable to affiliate
Amounts advanced by PMT	117,444	132,154
Other expenses	19,216	8,152
Payable to affiliates	$ 136,660	$ 140,306