Summary of Significant Accounting Policies - Loans Held-for-Sale (Detail) - USD ($)	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014
Loans Held-for-Sale
Loans held for sale carried at lower of cost or market.	$ 0	$ 0
Loans Held for Sale
Loans Held-for-Sale
Period of originated loans within which they are transferred or sold	60 days
Loans, non-accrual status	$ 0	$ 0

Recorded investment in financing receivables that are on nonaccrual status as of the balance sheet date.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 7
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=49124121&loc=d3e5111-111524

Name:	us-gaap_FinancingReceivableRecordedInvestmentNonaccrualStatus
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant