CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME
Net income	$ 26,136	$ 23,630	$ 39,895	$ 38,187
Other comprehensive income:
Net change in unrealized gains and (losses) on available-for-sale investments	1,652		1,652
Comprehensive income	$ 24,484	$ 23,630	$ 38,243	$ 38,187