CONSOLIDATED STATEMENTS OF CHANGES IN STOCKHOLDERS' EQUITY - USD ($) shares in Thousands, $ in Thousands	Common Stock. Common Stock	Common Stock.	Additional paid-in capital	Retained earnings	Noncontrolling interest in Private National Mortgage Acceptance Company, LLC	Common Stock	Total
Balance at Dec. 31, 2016	$ 2		$ 182,772	$ 164,549	$ 1,052,033		$ 1,399,356
Balance (in shares) at Dec. 31, 2016	22,427
Changes in stockholders' equity
Net income				100,757	210,765		311,522
Stock and unit-based compensation			7,545		14,406		21,951
Issuance of common stock in settlement of director fees			160		178		338
Repurchase of Class A common stock			(8,599)				$ (8,599)
Repurchase of Class A common stock (in shares)	(505)
Exchange of Class A units of Private National Mortgage Acceptance Company, LLC to Class A common stock of PennyMac Financial Services, Inc.			27,119		(27,119)
Exchange of Class A units of Private National Mortgage Acceptance Company, LLC to Class A common stock of PennyMac Financial Services, Inc. (in shares)	1,608						1,608
Repurchase of common stock						$ (8,599)
Repurchase of common stock (in shares)						(505)
Tax effect of exchange of Class A units of Private National Mortgage Acceptance Company, LLC to Class A common stock of PennyMac Financial Services, Inc.			(4,894)				$ (4,894)
Balance at Dec. 31, 2017	$ 2		204,103	265,306	1,250,263		1,719,674
Balance (in shares) at Dec. 31, 2017	23,530
Changes in stockholders' equity
Cumulative effect of change in accounting principle - Adoption of fair value accounting for all existing classes of mortgage servicing rights at fair value				189	587		776
Balance after adjustment	$ 2		204,103	265,495	1,250,850		1,720,450
Balance after adjustment (in shares)	23,530
Net income							66,926
Balance at Mar. 31, 2018							1,794,199
Balance at Dec. 31, 2017	$ 2		204,103	265,306	1,250,263		1,719,674
Balance (in shares) at Dec. 31, 2017	23,530
Changes in stockholders' equity
Net income				87,694	156,749		244,443
Stock and unit-based compensation			10,932		19,636		30,568
Stock and unit-based compensation (in shares)	299	23
Common stock dividends				(10,054)			(10,054)
Issuance of common stock in settlement of director fees							330
Issuance of Class A common stock in settlement of director fees			79		166		245
Repurchase of Class A common stock			(1,554)		(3,272)		$ (4,826)
Repurchase of Class A common stock (in shares)	(236)
Exchange of Class A units of Private National Mortgage Acceptance Company, LLC to Class A common stock of PennyMac Financial Services, Inc.	$ 1		33,155		(33,156)
Exchange of Class A units of Private National Mortgage Acceptance Company, LLC to Class A common stock of PennyMac Financial Services, Inc. (in shares)	1,635						1,635
Exchange of Class A common stock of subsidiary for common stock of PennyMac Financial Services, Inc. pursuant to a reorganization	$ (3)	$ 3
Exchange of Class A common stock of subsidiary for common stock of PennyMac Financial Services, Inc. pursuant to a reorganization (in shares)	(25,228)	25,228
Exchange of Class A unit of Private National Mortgage Acceptance Company, LLC for common stock of PennyMac Financial Services, Inc. pursuant to a reorganization, net of income tax effect		$ 5	1,064,315		$ (1,390,973)		$ (326,653)
Exchange of Class A unit of Private National Mortgage Acceptance Company, LLC for common stock of PennyMac Financial Services, Inc. pursuant to a reorganization, net of income tax effect (in shares)		52,263					52,263
Issuance of common stock in settlement of directors' fees			85				$ 85
Issuance of common stock in settlement of directors' fees (in shares)		4
Repurchase of common stock			(467)			$ (5,293)	(467)
Repurchase of common stock (in shares)		(24)				(260)
Balance at Dec. 31, 2018		$ 8	1,310,648	343,135			1,653,791
Balance (in shares) at Dec. 31, 2018		77,494
Balance at Mar. 31, 2018							1,794,199
Changes in stockholders' equity
Net income							68,405
Balance at Jun. 30, 2018							1,861,944
Changes in stockholders' equity
Net income							56,152
Balance at Sep. 30, 2018							1,916,710
Changes in stockholders' equity
Net income							52,960
Balance at Dec. 31, 2018		$ 8	1,310,648	343,135			1,653,791
Balance (in shares) at Dec. 31, 2018		77,494
Changes in stockholders' equity
Net income							46,135
Balance at Mar. 31, 2019							1,701,192
Balance at Dec. 31, 2018		$ 8	1,310,648	343,135			1,653,791
Balance (in shares) at Dec. 31, 2018		77,494
Changes in stockholders' equity
Net income				392,965			392,965
Stock and unit-based compensation			25,282				25,282
Stock and unit-based compensation (in shares)		1,062
Common stock dividends				(9,708)			(9,708)
Issuance of common stock in settlement of director fees			233				233
Issuance of common stock in settlement of director fees (in shares)		10
Repurchase of common stock			(1,056)			$ (1,056)	(1,056)
Repurchase of common stock (in shares)		(51)				(51)
Balance at Dec. 31, 2019		$ 8	1,335,107	726,392			2,061,507
Balance (in shares) at Dec. 31, 2019		78,515
Balance at Mar. 31, 2019							1,701,192
Changes in stockholders' equity
Net income							72,696
Balance at Jun. 30, 2019							1,778,997
Changes in stockholders' equity
Net income							121,473
Balance at Sep. 30, 2019							1,911,613
Changes in stockholders' equity
Net income							152,661
Balance at Dec. 31, 2019		$ 8	$ 1,335,107	$ 726,392			$ 2,061,507
Balance (in shares) at Dec. 31, 2019		78,515