Consolidated Statements of Comprehensive Income - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Comprehensive Income (Loss), Net of Tax, Attributable to Parent [Abstract]
Net income	$ 166,757	$ 170,751
Other comprehensive income, net of tax:
Change in value of derivatives	25	21
Other comprehensive income	25	21
Comprehensive income (loss)	$ 166,782	$ 170,772