Parent Company Information - Condensed Statements of Cash Flows (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
Cash flow from operating activities
Net income	$ 152,661	$ 121,473	$ 72,696	$ 46,135	$ 52,960	$ 56,152	$ 68,405	$ 66,926	$ 392,965	$ 244,443	$ 311,522
Net cash (used in) provided by operating activities									(2,245,123)	572,396	(883,412)
Cash flow from investing activities
Net cash provided by (used in) investing activities									148,782	(322,611)	(339,231)
Cash flow from financing activities
Issuance of common stock pursuant to exercise of stock options									5,145	5,317	1,254
Repurchase of common stock and Class A common stock									(1,056)	(5,293)	(8,599)
Payment of withholding taxes relating to stock-based compensation									(4,634)
Net cash provided by (used in) financing activities									2,128,995	(132,034)	1,161,174
Net change in cash and restricted cash									32,654	117,751	(61,469)
Cash and restricted cash at beginning of year				$ 155,924				38,173	155,924	38,173	99,642
Cash and restricted cash at end of year	188,578				$ 155,924				188,578	155,924	38,173
PennyMac Financial Services, Inc.
Cash flow from investing activities
Increase in investments in subsidiaries										(77)
Net cash provided by (used in) investing activities										(77)
Cash flow from financing activities
Payment of dividend to common stock and Class A common stockholders									(9,708)	(10,054)
Repurchase of common stock and Class A common stock									(1,056)	(1,554)	(8,599)
Payment of withholding taxes relating to stock-based compensation									(4,634)
PennyMac Financial Services, Inc. | Parent Company
Cash flow from operating activities
Net income									392,965	87,694	100,757
Equity in undistributed earnings of subsidiaries									(448,033)	(98,569)	(92,204)
Repricing of payable to exchanged Private National Mortgage Acceptance Company, LLC unitholders under tax receivable agreement											(32,940)
Decrease (increase) in intercompany receivable									8,962	(3,737)	5,646
Payments to exchanged Private National Mortgage Acceptance Company, LLC unitholders under tax receivable agreement											(6,726)
Increase in income taxes payable									58,609	22,889	29,912
Net cash (used in) provided by operating activities									12,503	8,277	4,445
Cash flow from financing activities
Issuance of common stock pursuant to exercise of stock options									5,145	803	1,254
Net cash provided by (used in) financing activities									(10,253)	(10,805)	(7,345)
Net change in cash and restricted cash									2,250	(2,605)	(2,900)
Cash and restricted cash at beginning of year								$ 2,605		$ 2,605	5,505
Cash and restricted cash at end of year	$ 2,250								$ 2,250		$ 2,605