CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 8,226	$ 6,504	$ 15,415	$ 9,616
Other comprehensive income (loss):
Unrealized holding gains (losses) on securities arising during the period	(5,976)	543	(7,069)	629
Income tax effect	2,092	(190)	2,475	(220)
Unrealized holding gain on securities transferred from the held-to-maturity category into the available-for-sale category	0	8,509	0	8,509
Income tax effect	0	(2,978)	0	(2,978)
Reclassification adjustment for gains included in net income	0	(8,797)	0	(9,006)
Income tax effect	0	3,079	0	3,152
Other comprehensive income (loss), net of tax	(3,884)	166	(4,594)	86
Comprehensive income	$ 4,342	$ 6,670	$ 10,821	$ 9,702