Derivative Assets And Collateral Received (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Derivative [Line Items]
Gross amounts of recognized assets	$ 80,976	$ 121,654
Derivative Assets not subject to master netting agreements	10,100	33,700
Derivatives, Interest Rate Contracts | Subject to Master Netting Agreements
Derivative [Line Items]
Gross amounts of recognized assets	70,902	87,962
Gross amounts offset in the Statement of Condition	0	0
Net amounts of assets presented in the Statement of Condition	70,902	87,962
Derivative liabilities available for offset	(23,283)	(25,953)
Collateral Received	(43,379)	(52,888)
Net amount	$ 4,240	$ 9,121