Accumulated Other Comprehensive Income (Loss) (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Accumulated Other Comprehensive Income [Roll Forward]
AOCI - beginning balance			$ (6,410)	$ (5,499)
Other comprehensive income before reclassifications			11,394	(11,550)
Amounts reclassified from accumulated other comprehensive income			(834)	851
Period change	(60)	(1,019)	10,560	(10,699)
AOCI - ending balance	4,150	(16,198)	4,150	(16,198)
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			11,338	(12,646)
Amounts reclassified from accumulated other comprehensive income			(1,518)	(317)
Period change			9,820	(12,963)
AOCI - ending balance	11,386	4,941	11,386	4,941
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			1,701	89
Amounts reclassified from accumulated other comprehensive income
Period change			1,701	89
AOCI - ending balance	(146)	(3,183)	(146)	(3,183)
Unrealized Gains (Losses) on Cash Flow Hedges
Accumulated Other Comprehensive Income [Roll Forward]
AOCI - beginning balance			(501)	(2,652)
Other comprehensive income before reclassifications			(1,645)	1,007
Amounts reclassified from accumulated other comprehensive income			684	382
Period change			(961)	1,389
AOCI - ending balance	(1,462)	(1,263)	(1,462)	(1,263)
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				786
Period change			0	786
AOCI - ending balance	$ (5,628)	$ (16,693)	$ (5,628)	$ (16,693)