Organization and Basis of Presentation - Accumulated Other Comprehensive Loss Summary (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	$ 6,393,844
Cumulative effect upon adoption of ASU		$ 181
Balance at period end	6,317,195
Accumulated Other Comprehensive Loss, Net [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	(13,217)
Cumulative effect upon adoption of ASU		175
Other comprehensive income (loss) before reclassification	92
Amounts reclassified from accumulated other comprehensive loss	(1,867)
Other comprehensive income	(1,600)
Balance at period end	(14,817)
Change in Fair Value and Amortization of Swap Settlements [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	(13,077)
Cumulative effect upon adoption of ASU		175
Other comprehensive income (loss) before reclassification	(27)
Amounts reclassified from accumulated other comprehensive loss	(1,899)
Other comprehensive income	(1,751)
Balance at period end	(14,828)
Unrealized Gains/(Loss) on Available for Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	(140)
Cumulative effect upon adoption of ASU		$ 0
Other comprehensive income (loss) before reclassification	119
Amounts reclassified from accumulated other comprehensive loss	32
Other comprehensive income	151
Balance at period end	$ 11