Organization and Basis of Presentation - Accumulated Other Comprehensive Loss Summary (Details) $ in Thousands	3 Months Ended
	Mar. 31, 2017 USD ($)
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	$ 6,292,237
Balance at period end	6,389,003
AOCI Attributable to Parent [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	(32,098)
Other comprehensive income before reclassification	5,669
Amounts reclassified from accumulated other comprehensive loss	(3,530)
Other comprehensive income (loss)	2,139
Balance at period end	(29,959)
Change in Fair Value and Amortization of Swap Settlements [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	(32,963)
Other comprehensive income before reclassification	5,496
Amounts reclassified from accumulated other comprehensive loss	(1,978)
Other comprehensive income (loss)	3,518
Balance at period end	(29,445)
Unrealized Gains on Available for Sale Securities [Member]
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Balance at period beginning	865
Other comprehensive income before reclassification	173
Amounts reclassified from accumulated other comprehensive loss	(1,552)
Other comprehensive income (loss)	(1,379)
Balance at period end	$ (514)