Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Increase (Decrease) in Stockholders' Equity [Roll Forward]
AOCI - beginning balance	$ (5,499)	$ (3,602)
Other comprehensive income before reclassifications	(1,850)	270
Amounts reclassified from accumulated other comprehensive income	601	7
Other Comprehensive Income, net of tax	(1,249)	277
AOCI - ending balance	(6,748)	(3,325)
Net unrealized gain on securities available for sale
Increase (Decrease) in Stockholders' Equity [Roll Forward]
AOCI - beginning balance	17,904	18,244
Other comprehensive income before reclassifications	(2,115)	(20)
Amounts reclassified from accumulated other comprehensive income	(161)	(513)
Other Comprehensive Income, net of tax	(2,276)	(533)
AOCI - ending balance	15,628	17,711
Net unrealized loss on securities available for sale for which a portion of an other-than-temporary impairment has been recognized in income
Increase (Decrease) in Stockholders' Equity [Roll Forward]
AOCI - beginning balance	(3,272)	(3,168)
Other comprehensive income before reclassifications	72	(14)
Amounts reclassified from accumulated other comprehensive income
Other Comprehensive Income, net of tax	72	(14)
AOCI - ending balance	(3,200)	(3,182)
Net unrealized loss on cash flow hedges
Increase (Decrease) in Stockholders' Equity [Roll Forward]
AOCI - beginning balance	(2,652)	(1,841)
Other comprehensive income before reclassifications	193	304
Amounts reclassified from accumulated other comprehensive income	122
Other Comprehensive Income, net of tax	315	304
AOCI - ending balance	(2,337)	(1,537)
Defined benefit plans
Increase (Decrease) in Stockholders' Equity [Roll Forward]
AOCI - beginning balance	(17,479)	(16,837)
Other comprehensive income before reclassifications
Amounts reclassified from accumulated other comprehensive income	640	520
Other Comprehensive Income, net of tax	640	520
AOCI - ending balance	$ (16,839)	$ (16,317)