Derivative Financial Instruments - Offsetting Assets and Liabilities (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014		Dec. 31, 2013
Other Assets
Gross position	$ 5,238		$ 6,761
Impact of master netting agreement	(4,045)		(4,981)
Derivative values with impact of master netting agreements (as carried on balance sheet)	1,193		1,780
Cash collateral (held) pledged	(900)	[1]	(5,190)	[1]
Net position	293		(3,410)
Other Liabilities
Gross position	(28,688)		(6,149)
Impact of master netting agreement	4,045		4,981
Derivative values with impact of master netting agreements (as carried on balance sheet)	(24,643)		(1,168)
Cash collateral (held) pledged	72,478	[1]	40	[1]
Net position	$ 47,835		$ (1,128)

[1] Cash collateral amount calculations include outstanding accrued interest payable/receivable.