Income Taxes - Deferred Tax Assets And Liabilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Deferred expense:
Mortgage servicing rights	$ 46,064
Investment in PennyMac		$ 34,011	$ 40,493
Net operating loss	(14,902)	(9,675)	8,110
Compensation accruals	(3,596)
Reserves and losses	(1,848)
Additional tax basis in partnership from exchanges of partnership units into the Company's common stock	(1,391)
Other	(1,302)
Tax credits	(57)	76	(634)
Total provision for deferred income taxes	22,968	24,412	$ 47,969
Components of Deferred tax asset:
Taxes currently receivable		(2,126)
Taxes currently payable	218
Components of income taxes payable:
Deferred income tax liabilities, net	400,328	54,286
Income taxes payable	400,546	52,160
Deferred income tax assets:
Additional tax basis in partnership from exchanges of partnership units into the Company's common stock	44,165
Compensation accruals	28,752
Reserves and losses	26,589
Net operating loss carryforward	25,104	10,202
Tax credits carryforward	616	558
Gross deferred tax assets	125,226	10,760
Deferred income tax liabilities:
Mortgage servicing rights	517,042
Investment in PennyMac		65,046
Other	8,512
Gross deferred tax liabilities	525,554	65,046
Deferred income tax liabilities, net	400,328	54,286
Net operating loss carryforward	93,500
Net operating loss carryforward, expiring 2035	1,300
Net operating loss carryforward, expiring 2037	35,200
Net operating loss carryforward, no expiration date	57,000
Tax credits with no expiration date	600
Unrecognized tax benefits	0	0
Accrual of interest or penalties related to unrecognized tax benefits	$ 0	$ 0