Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Accumulated Other Comprehensive Income [Roll Forward]
AOCI - beginning balance	$ (6,410)	$ (5,499)
Other comprehensive income before reclassifications	5,548	(1,850)
Amounts reclassified from accumulated other comprehensive income	(154)	601
Period change	5,394	(1,249)
AOCI - ending balance	(1,016)	(6,748)
Unrealized Gains (Losses) on Securities Available for Sale
Accumulated Other Comprehensive Income [Roll Forward]
AOCI - beginning balance	1,566	17,904
Other comprehensive income before reclassifications	5,207	(2,115)
Amounts reclassified from accumulated other comprehensive income	(378)	(161)
Period change	4,829	(2,276)
AOCI - ending balance	6,395	15,628
Unrealized Gains (Losses) on Securities Available for Sale for which a Portion of Other-Than-Temporary Impairment has been Recognized in Income
Accumulated Other Comprehensive Income [Roll Forward]
AOCI - beginning balance	(1,847)	(3,272)
Other comprehensive income before reclassifications	1,164	72
Amounts reclassified from accumulated other comprehensive income
Period change	1,164	72
AOCI - ending balance	(683)	(3,200)
Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income [Roll Forward]
AOCI - beginning balance	(501)	(2,652)
Other comprehensive income before reclassifications	(823)	193
Amounts reclassified from accumulated other comprehensive income	224	122
Period change	(599)	315
AOCI - ending balance	(1,100)	(2,337)
Unrealized Gains (Losses) on Defined Benefit Plans
Accumulated Other Comprehensive Income [Roll Forward]
AOCI - beginning balance	(5,628)	(17,479)
Other comprehensive income before reclassifications
Amounts reclassified from accumulated other comprehensive income		640
Period change	0	640
AOCI - ending balance	$ (5,628)	$ (16,839)