CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Statement Of Income And Comprehensive Income [Abstract]
Net Income	$ 9,740	$ 6,444
Other comprehensive income (loss):
Unrealized (losses) gains on securities available for sale	(7,725)	540
Tax expense	2,898	(224)
Net of tax amount	(4,827)	316
Reclassification adjustment for gains included in net income	(1,644)	(2,036)
Tax expense	625	774
Net of tax amount	(1,019)	(1,262)
Total other comprehensive loss	(5,846)	(946)
Total comprehensive income	$ 3,894	$ 5,498