Accumulated Other Comprehensive Income (Details) (USD $) In Thousands, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ 9,983	$ 47,962
Accumulated Net Unrealized Gain (Loss) on Available-For-Sale Securities
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), before Tax	18,343	95,328
Tax effect	(7,136)	(37,083)
Accumulated Other Comprehensive Income (Loss), Net of Tax	11,207	58,245
Accumulated Net Unrealized Gain (Loss) on Derivatives Used for Cash Flow Hedges
Accumulated Other Comprehensive Income (Loss)
Accumulated Other Comprehensive Income (Loss), before Tax	(2,004)	(16,832)
Tax effect	780	6,549
Accumulated Other Comprehensive Income (Loss), Net of Tax	$ (1,224)	$ (10,283)