Noncontrolling Interest (Details) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended		9 Months Ended
	Nov. 01, 2018	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Net income and the effects of changes in noncontrolling interest
Net income attributable to PennyMac Financial Services, Inc. common stockholders		$ 121,473	$ 14,489	$ 240,304	$ 48,945
Increase in the Company's additional paid-in capital for exchanges of Class A units of Private National Mortgage Acceptance Company, LLC to Class A common stock of PennyMac Financial Services, Inc.			$ 4,377		$ 32,501
Shares of Class A common stock of PennyMac Financial Services, Inc. issued pursuant to exchange of Class A units of Private National Mortgage Acceptance Company, LLC by noncontrolling interest unitholders and issued as equity compensation (in shares)			131		1,616
New PFSI | Class A Unit
Noncontrolling Interest [Line Items]
Common stock conversion ratio (as a percent)	100.00%
Noncontrolling interest in Private National Mortgage Acceptance Company, LLC
Net income and the effects of changes in noncontrolling interest
Increase in the Company's additional paid-in capital for exchanges of Class A units of Private National Mortgage Acceptance Company, LLC to Class A common stock of PennyMac Financial Services, Inc.			$ (4,377)		$ (32,502)