Transactions with Affiliates - Exchanged Private National Mortgage Acceptance Company, LLC Unitholders (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Transactions with Affiliates
Amount of tax benefits under the tax sharing agreement (as a percent)	85.00%
Federal income tax statutory rate (as a percent)	21.00%	35.00%	35.00%
Private National Mortgage Acceptance Company, LLC
Transactions with Affiliates
Reduction in payable to exchanged Private National Mortgage Acceptance Company, LLC		$ 32,000
Liability resulting from unit exchanges	$ 3,652	7,723	$ 2,190
Payments to exchanged Private National Mortgage Acceptance Company, LLC unitholders under tax receivable agreement		(6,726)
Repricing of payable to exchanged Private National Mortgage Acceptance Company, LLC unitholders under tax receivable agreement	(1,126)	(32,940)	(551)
Payable to exchanged PNMAC unitholders under tax receivable agreement	46,537	$ 44,011	$ 75,954
Payment of tax liability under the tax receivable agreement to Private National Mortgage Acceptance Company, LLC unitholders	$ 32,000