Income Taxes - Deferred Tax Assets And Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018
Deferred expense:
Mortgage servicing rights	$ 91,592	$ 46,064
Net operating loss	23,445	(14,902)	$ (9,675)
Compensation accruals	(12,286)	(3,596)
Reserves and losses	(2,945)	(1,848)
Additional tax basis in partnership from exchanges of partnership units into the Company's common stock	4,269	(1,391)
Other	6,106	(1,302)
Tax credits	566	(57)	76
Investment in PennyMac			34,011
Total provision for deferred income taxes	110,747	22,968	$ 24,412
Components of income taxes payable:
Income taxes currently (receivable)	(6,506)
Income taxes currently payable		218
Deferred income tax liabilities, net	511,075	400,328
Income taxes payable	504,569	400,546		$ 480,559	$ 441,336	$ 414,636	$ 74,158	$ 67,357	$ 58,956
Deferred income tax assets:
Compensation accruals	41,038	28,752
Additional tax basis in partnership from exchanges of partnership units into the Company's common stock	39,897	44,165
Reserves and losses	29,534	26,589
Net operating loss carryforward	1,658	25,104
Tax credits carryforward	50	616
Gross deferred tax assets	112,177	125,226
Deferred income tax liabilities:
Mortgage servicing rights	608,635	517,042
Other	14,617	8,512
Gross deferred tax liabilities	623,252	525,554
Deferred income tax liabilities, net	511,075	400,328
Tax credits with no expiration date	100
Unrecognized tax benefits	0	0
Accrual of interest or penalties related to unrecognized tax benefits	$ 0	$ 0