Derivatives and Balance Sheet Offsetting Balance Sheet Offsetting (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Balance Sheet Offsetting [Line Items]
Repurchase agreements, amounts offset in balance sheet	$ 0	$ 0
repurchase agreements, net amount presented in statement of financial position	80,822	99,699
Securities Sold under Agreements to Repurchase, Collateral, Right to Reclaim Securities	(80,822)	(99,699)
securities sold under agreements to repurchase, amount not offset	0	0
Interest Rate Contracts [Member]
Balance Sheet Offsetting [Line Items]
Derivative Assets, Gross Amounts Offset in the Balance Sheets	0	0
Derivative Asset	9,012	12,438
Derivative, Collateral, Obligation to Return Securities	0	0
Derivative Asset, Fair Value, Amount Not Offset Against Collateral	9,012	12,438
Derivative Liability, Gross Amounts Offset in Balance Sheets	0	0
Derivative Liability	9,036	12,478
Derivative, Collateral, Right to Reclaim Securities	(9,036)	(12,478)
Derivative Liability, Fair Value, Amount Not Offset Against Collateral	0	0
Available-for-sale Securities [Member]
Balance Sheet Offsetting [Line Items]
Assets Sold under Agreements to Repurchase, Carrying Amount	$ 80,822	$ 99,699