Accumulated Other Comprehensive Income (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
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Tax benefit	$ 4,907	$ 5,848	$ 14,995	$ 16,313
Net income	10,924	12,653	33,259	36,415
Unrealized gains (losses) on AFS securities [Member] | Reclassification Out Of Accumulated Other Comprehensive Income [Member]
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Securities losses	(34)	(23)	(145)	(31)
Tax benefit	(12)	(8)	(51)	(11)
Net income	$ (22)	$ (15)	$ (94)	$ (20)