CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Statement of Comprehensive Income [Abstract]
Net income	$ 8,385	$ 10,082	$ 19,840	$ 26,743
Other comprehensive income:
Unrealized gain (loss) on available-for-sale securities, net of tax	(17)	26	(5)	7
Comprehensive income	$ 8,368	$ 10,108	$ 19,835	$ 26,750