Condensed Consolidated Statements of Comprehensive Income (Unaudited) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Net income	$ 98,994	$ 112,760	$ 181,614	$ 185,421
Other comprehensive income, net of tax:
Unrealized gain on marketable securities, available for sale				39
Total comprehensive income	$ 98,994	$ 112,760	$ 181,614	$ 185,460