Derivative Liabilities and Collateral Pledged (Details) (USD $)	Mar. 31, 2015		Dec. 31, 2014	Mar. 31, 2014
Derivative [Line Items]
Gross amounts of recognized liabilities	$ 133,273,000		$ 119,239,000	$ 137,863,000
Derivative Liabilities not subject to master netting agreements	12,800,000			7,700,000
Subject to Master Netting Agreements
Derivative [Line Items]
Gross amounts of recognized liabilities	120,429,000	[1]		130,180,000	[1]
Gross amounts offset in the Statement of Condition	0	[1]		0	[1]
Net amounts of liabilities presented in the Statement of Condition	120,429,000	[1],[2]		130,180,000	[1],[2]
Derivative assets available for offset	(14,053,000)	[1]		(33,495,000)	[1]
Collateral pledged	(82,440,000)	[1]		(91,331,000)	[1]
Net amount	23,936,000	[1]		5,354,000	[1]
Derivatives, Interest Rate Contracts | Subject to Master Netting Agreements
Derivative [Line Items]
Gross amounts of recognized liabilities	120,429,000
Net amounts of liabilities presented in the Statement of Condition	$ 120,429,000

[1] 2015and 2014 are comprised entirely of interest rate derivative contracts.

[2] Included in Derivative Liabilities on the Consolidated Condensed Statements of Condition. As of March 31, 2015 and 2014, $12.8 million and $7.7 million, respectively, of derivative liabilities (primarily capital markets forward contracts) have been excluded from these tables because they are generally not subject to master netting or similar agreements.