Noncontrolling Interest (Details) - USD ($) shares in Thousands, $ in Thousands		3 Months Ended
	Nov. 01, 2018	Mar. 31, 2019	Mar. 31, 2018
Net income and the effects of changes in noncontrolling interest
Net income attributable to PennyMac Financial Services, Inc. common stockholders		$ 46,135	$ 16,619
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.			$ 14,859
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)			748
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.			$ (14,859)