Accumulated Other Comprehensive Income (Loss) (Change in AOCI Components net of tax) (Details 2) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at Beginning of Period	$ (31,823)	$ 29,208
Other Comprehensive Income Before Reclassifications	6,473	(7,763)
Amounts Reclassified from Accumulated Other Comprehensive Income	(46)	(1,800)
Total Other Comprehensive Income (Loss)	6,427	(9,563)
Balance at End of Period	(25,396)	19,645
Defined Benefit Plans
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at Beginning of Period	(22,394)	(30,569)
Other Comprehensive Income Before Reclassifications	0	(125)
Amounts Reclassified from Accumulated Other Comprehensive Income	156	203
Total Other Comprehensive Income (Loss)	156	78
Balance at End of Period	(22,238)	(30,491)
Available-for-sale Securities | Unrealized Gains and Losses on Net Investment Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at Beginning of Period	(1,300)	45,996
Other Comprehensive Income Before Reclassifications	6,473	(7,638)
Amounts Reclassified from Accumulated Other Comprehensive Income	0	0
Total Other Comprehensive Income (Loss)	6,473	(7,638)
Balance at End of Period	5,173	38,358
Held-to-maturity Securities | Unrealized Gains and Losses on Net Investment Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at Beginning of Period	(8,129)	13,781
Other Comprehensive Income Before Reclassifications	0	0
Amounts Reclassified from Accumulated Other Comprehensive Income	(202)	(2,003)
Total Other Comprehensive Income (Loss)	(202)	(2,003)
Balance at End of Period	$ (8,331)	$ 11,778