Schedule III Part II - Summary of Real Estate and Accumulated Depreciation (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Real Estate and Accumulated Depreciation, Carrying Amount of Land and Buildings and Improvements [Abstract]
Balance at beginning of year	$ 7,635,061	$ 6,759,073	$ 6,064,406
Acquisitions	14,940	555,476	229,296
Improvements	407,225	492,541	483,932
Deduction during period—dispositions and retirements of property	(237,754)	(172,029)	(18,561)
Balance at end of year	7,819,472	7,635,061	6,759,073
Aggregate cost basis for Federal tax purposes	7,200,000
Reconciliation of Real Estate Accumulated Depreciation [Roll Forward]
Balance at beginning of year	1,876,544	1,729,234	1,574,041
Additions during period—depreciation and amortization expense	215,969	193,340	173,244
Deductions during period—dispositions and retirements of property	(33,370)	(46,030)	(18,051)
Balance at end of year	$ 2,059,143	$ 1,876,544	$ 1,729,234