Guarantees (Details) (USD $)	9 Months Ended
Sep. 30, 2013	Dec. 31, 2012
Guarantees [Abstract]
Standby letters of credit outstanding	$ 27,063,000	$ 17,064,000
Letters of credit maximum expiration period, Years	1 year

The total amount of the contingent obligation under letters of credit outstanding as of the reporting date.

No definition available.

Name:	us-gaap_LettersOfCreditOutstandingAmount
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant