Parent Company Information - Condensed Statements of Income (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
Expenses
Interest									$ 211,979	$ 144,597	$ 144,520
Total expenses	$ 287,009	$ 270,150	$ 203,387	$ 187,414	$ 192,895	$ 189,232	$ 169,600	$ 165,205	947,960	716,932	619,554
Income before provision for income taxes	203,366	166,197	99,590	60,291	58,306	61,697	74,698	72,996	529,444	267,697	335,909
Provision for income taxes	50,705	44,724	26,894	14,156	5,346	5,545	6,293	6,070	136,479	23,254	24,387
Net income	$ 152,661	$ 121,473	$ 72,696	$ 46,135	$ 52,960	$ 56,152	$ 68,405	$ 66,926	392,965	244,443	311,522
Private National Mortgage Acceptance Company, LLC
Revenue
Repricing of payable to exchanged Private National Mortgage Acceptance Company, LLC unitholders under tax receivable agreement									379	1,126	32,940
PennyMac Financial Services, Inc. | Parent Company
Revenue
Dividends from subsidiaries									36,376	10,054
Repricing of payable to exchanged Private National Mortgage Acceptance Company, LLC unitholders under tax receivable agreement											32,940
Total net revenue									36,376	10,054	32,940
Expenses
Interest									153	32
Total expenses									153	32
Income before provision for income taxes									36,223	10,022	32,940
Provision for income taxes									91,291	20,897	24,387
Income before equity in undistributed earnings of subsidiaries									(55,068)	(10,875)	8,553
Equity in undistributed earnings of subsidiaries									448,033	98,569	92,204
Net income									$ 392,965	$ 87,694	100,757
PennyMac Financial Services, Inc. | Parent Company | Private National Mortgage Acceptance Company, LLC
Revenue
Repricing of payable to exchanged Private National Mortgage Acceptance Company, LLC unitholders under tax receivable agreement											$ 32,940