Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Statement Of Income And Comprehensive Income [Abstract]
Net Income	$ 16,911	$ 9,740
Other comprehensive (loss) income:
Unrealized (losses) gains on securities available-for-sale	14,749	(7,725)
Tax benefit (expense)	(5,604)	2,898
Net of tax amount	9,145	(4,827)
Reclassification adjustment for gains included in net income	(578)	(1,644)
Tax expense	220	625
Net of tax amount	(358)	(1,019)
Total other comprehensive (loss) income	8,787	(5,846)
Total comprehensive income	$ 25,698	$ 3,894