Schedule III - REAL ESTATE AND ACCUMLATED DEPRECIATION (Reconciliation of Real Estate and Accumulated Depreciation) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Reconciliation of Real Estate
Balance at beginning of year	$ 4,979,840	$ 4,774,632	$ 4,116,556
Change in land	93,833	122,446	95,095
Additions	790,183	830,896	834,346
Impairments	0	(35,734)	0
Dispositions and write-offs and land costs of sales	(508,447)	(712,400)	(271,365)
Balance at end of year	5,355,409	4,979,840	4,774,632
Reconciliation of Accumulated Depreciation
Balance at beginning of year	245,814	232,969	157,182
Depreciation expense	116,401	81,878	82,275
Dispositions and write-offs	(40,333)	(69,033)	(6,488)
Balance at end of year	$ 321,882	$ 245,814	$ 232,969
Building and Building Improvements | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Estimated useful lives of assets	10 years
Building and Building Improvements | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Estimated useful lives of assets	45 years
Equipment and fixtures | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Estimated useful lives of assets	5 years
Equipment and fixtures | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Estimated useful lives of assets	10 years
Computer, Hardware and Software and Vehicles | Minimum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Estimated useful lives of assets	3 years
Computer, Hardware and Software and Vehicles | Maximum
REAL ESTATE AND ACCUMULATED DEPRECIATION
Estimated useful lives of assets	5 years