Net Interest Income (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Interest income:
Cash and short-term investments	$ 1,893	$ 2,706	$ 3,604	$ 4,639
Loans held for sale at fair value	32,586	34,366	79,012	65,709
Placement fees relating to custodial funds	12,047	32,136	35,256	55,397
Interest income, excluding related parties	46,526	69,208	117,872	125,745
Interest income	47,318	70,900	119,882	129,233
Interest expense:
Assets sold under agreements to repurchase	17,487	19,645	43,171	28,280
Mortgage loan participation purchase and sale agreements	1,061	2,419	2,871	4,730
Obligations under capital lease	104	136	271	202
Notes payable	11,581	18,039	26,930	36,034
Interest shortfall on repayments of mortgage loans serviced for Agency securitizations	18,954	8,214	33,825	12,525
Interest on mortgage loan impound deposits	1,648	1,704	3,305	2,863
Interest expense, non-affiliates	50,835	50,157	110,373	84,634
Interest expense	53,207	52,924	114,719	90,467
Net interest (expense) income	(5,889)	17,976	5,163	38,766
PMT
Interest income:
From PennyMac Mortgage Investment Trust	792	1,692	2,010	3,488
Interest expense:
To PennyMac Mortgage Investment Trust Excess servicing spread financing at fair value	2,372	2,767	4,346	5,833
Assets sold under agreements to repurchase
Interest expense:
Assets sold under agreements to repurchase	$ 17,487	19,645	$ 43,171	28,280
Incentives recorded		$ 3,900		$ 13,200