Transactions with Related Parties - Summary of Correspondent Production Activity (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Related Party Transaction [Line Items]
Loan fulfillment fees earned by PLS	$ 29,590	$ 14,559	$ 57,164	$ 26,503
Purchases of loans acquired for sale from PLS			2,218,721	1,427,637
Loans included in loans acquired for sale at fair value pending sale to PLS	2,477,267		2,477,267		$ 1,643,957
PennyMac Loan Services, LLC [Member]
Related Party Transaction [Line Items]
Loan fulfillment fees earned by PLS	29,590	14,559	57,164	26,503
UPB of loans fulfilled by PLS	10,741,078	5,396,370	18,876,630	9,622,001
Sourcing fees received from PLS included in Net gain on loans acquired for sale	3,155	2,891	5,149	5,532
UPB of loans sold to PLS	10,514,390	9,639,495	17,161,728	18,487,368
Purchases of loans acquired for sale from PLS	1,334,211	646,311	2,218,721	1,427,637
Tax service fee paid to PLS included in Other expense	3,102	$ 1,542	5,345	$ 2,750
Loans included in loans acquired for sale at fair value pending sale to PLS	$ 258,211		$ 258,211		$ 86,308