CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 9,699	$ 7,121	$ 26,194	$ 20,127
Other comprehensive income:
Unrealized gain/(loss) on securities, net of tax	(1,045)	1,449	(5,650)	1,899
Comprehensive income	$ 8,654	$ 8,570	$ 20,544	$ 22,026