Earnings Per Share of Common Stock (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands		3 Months Ended
	Nov. 01, 2018	Mar. 31, 2019	Mar. 31, 2018
Basic earnings per share of common stock:
Net income attributable to common stockholders		$ 46,135	$ 16,619
Weighted-average common stock outstanding		77,653	23,832
Basic earnings per share of common stock (in dollars per share)		$ 0.59	$ 0.70
Diluted earnings per share of common stock:
Net income attributable to common stockholders		$ 46,135	$ 16,619
Net income attributable to dilutive stock-based compensation units			1,400
Effect of net income attributable to noncontrolling interest, net of tax			35,449
Net income attributable to common stockholders for diluted earnings per share		$ 46,135	$ 53,468
Weighted-average common stock outstanding applicable to basic earnings per share		77,653	23,832
Effect of dilutive shares:
Common shares issuable under stock-based compensation plan		$ 1,633	$ 2,947
PennyMac Class A units exchangeable to common stock			52,682
Weighted-average shares of common stock outstanding applicable to diluted earnings per share		79,286	79,461
Diluted earnings per share of common stock (in dollars per share)		$ 0.58	$ 0.67
Total anti-dilutive stock-based compensation units		2,046	306
Performance-based RSUs
Effect of dilutive shares:
Total anti-dilutive stock-based compensation units		1,279	134
Stock Options
Effect of dilutive shares:
Total anti-dilutive stock-based compensation units		706	172
Weighted-average exercise price of anti-dilutive stock options		$ 24.26	$ 24.40
Time-based RSUs
Effect of dilutive shares:
Total anti-dilutive stock-based compensation units		61
Class A Unit | New PFSI
Common stock conversion ratio (as a percent)	100.00%