Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Net income	$ 53,143	$ 53,369	$ 64,613
Other Comprehensive Income (Loss):
Unrealized gains (losses) on investments in marketable securities	(17,740)	30,416	(7,211)
Reclassification adjustment for realized gains on sale of securities	(566)	(379)	(39)
Income tax (expense) benefit related to items of other comprehensive income (loss)	7,062	(11,614)	2,627
Other comprehensive income (loss), net of tax	(11,244)	18,423	(4,623)
Comprehensive Income	$ 41,899	$ 71,792	$ 59,990