Mortgage Loans Acquired for Sale at Fair Value - Additional Information (Detail)	12 Months Ended
Dec. 31, 2016
Minimum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Sourcing fee on average number of calendar days mortgage loans are held prior to purchase by PLS	0.02%
Maximum [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
Sourcing fee on average number of calendar days mortgage loans are held prior to purchase by PLS	0.035%

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_FairValueBalanceSheetGroupingFinancialStatementCaptionsLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration