Contingencies and Commitments (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Outstanding Commitments
Outstanding commitments	$ 1,351,398	$ 1,263,338
Commitments to Extend Credit
Outstanding Commitments
Outstanding commitments	1,325,236	1,240,923
Letters of Credit
Outstanding Commitments
Outstanding commitments	$ 26,162	$ 22,415

Minimum amount of other commitment not otherwise specified in the taxonomy. Excludes commitments explicitly modeled in the taxonomy, including but not limited to, long-term and short-term purchase commitments, recorded and unrecorded purchase obligations, supply commitments, registration payment arrangements, leases, debt, product warranties, guarantees, environmental remediation obligations, and pensions.

No definition available.

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