Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ (7,475)	[1]	$ (17,605)
Other comprehensive income before reclassifications	1,337		3,292
Amounts reclassified from accumulated other comprehensive income	2		0
Other comprehensive income (loss), net of tax	1,339		3,292
Ending balance	(6,136)		(14,313)
Unrealized gains (losses) on available for sale securities [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(3,017)		(14,476)
Other comprehensive income before reclassifications	1,660		3,267
Amounts reclassified from accumulated other comprehensive income	0		0
Other comprehensive income (loss), net of tax	1,660		3,267
Ending balance	(1,357)		(11,209)
Interest rate swaps
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(324)		0
Other comprehensive income before reclassifications	(323)		25
Amounts reclassified from accumulated other comprehensive income	2		0
Other comprehensive income (loss), net of tax	(321)		25
Ending balance	(645)		25
Defined benefit plan items [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(4,134)		(3,129)
Other comprehensive income before reclassifications	0		0
Amounts reclassified from accumulated other comprehensive income	0		0
Other comprehensive income (loss), net of tax	0		0
Ending balance	$ (4,134)		$ (3,129)

[1] Derived from audited consolidated financial statements