Stockholders' Equity and EPS - Activity Related to Net Gains on Cash Flow Hedges in AOCI (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Cash flow hedge gains expected to reclassified out of AOCI over next 12 months			$ 1,500
Beginning balance	$ 5,483,823	$ 4,559,724	5,264,843	$ 4,319,415
Ending balance	5,706,175	4,804,841	5,706,175	4,804,841
Accumulated Gain (Loss), Net, Cash Flow Hedge, Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	797	0	0	0
Net increase in fair value, net of tax	12,664	0	13,459	0
Net realized loss reclassified to net income, net of tax	367	0	369	0
Ending balance	$ 13,828	$ 0	$ 13,828	$ 0