Loans - Defaults on Troubled Debt Restructurings (Details) - item	3 Months Ended
Mar. 31, 2017	Mar. 31, 2016
Loans
Default period contractually past due under modified terms (in days)	30 days
Number of defaults on troubled debt restructurings	0	0
Period of consecutive payments (in months)	6 months

Number of financing receivables that have been modified by troubled debt restructurings within the previous 12 months and for which there was a payment default.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 310
-SubTopic 10
-Section 50
-Paragraph 34
-URI http://asc.fasb.org/extlink&oid=66008989&loc=SL6953682-111524

Name:	us-gaap_FinancingReceivableModificationsSubsequentDefaultNumberOfContracts1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration