Significant Accounting Policies and Recently Issued Accounting Pronouncement - Fulfillment Fees and Management Fees (Details)	12 Months Ended
Dec. 31, 2018
Fulfillment Fees
Number of days from purchase fulfillment fees are collected	30 days
Management fees
The period from quarter end that management fees are collected	30 days

The number of days from purchase that fulfillment fees are collected.

No definition available.

Name:	pfsi_FulfillmentFeesPeriodOfCollectionFromPurchase
Namespace Prefix:	pfsi_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration