Stockholders' Equity and EPS - Activity Related to Net Gains on Cash Flow Hedges in AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cash flow hedge gains expected to reclassified out of AOCI over next 12 months			$ 1,900
Balance, beginning of period, net of tax	$ 5,706,175	$ 4,804,841	5,264,843	$ 4,319,415
Balance, end of period, net of tax	6,048,469	5,070,045	6,048,469	5,070,045
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balance, beginning of period, net of tax	13,828	0	0	0
Net increase in fair value, net of tax	7,077	0	20,536	0
Net realized loss reclassified to net income, net of tax	1,958	0	2,327	0
Balance, end of period, net of tax	$ 22,863	$ 0	$ 22,863	$ 0