Schedule III - REAL ESTATE AND ACCUMLATED DEPRECIATION (Details 2)-K (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Reconciliation of Real Estate
Balance at beginning of year	$ 3,024,833	$ 2,746,596	$ 2,589,730
Change in land		296,147	90,124	66,889
Additions	973,833	352,141	179,372
Dispositions and write-offs and land costs of sales	(178,257)	(164,028)	(89,395)
Balance at end of year	4,116,556	3,024,833	2,746,596	2,589,730
Reconciliation of Accumulated Depreciation
Balance at beginning of year	111,728	112,491	91,605
Depreciation Expense		(50,683)	(29,637)	(19,457)
Dispositions and write-offs	(5,229)	(30,400)	1,429
Balance at end of year	$ 157,182	$ 111,728	$ 112,491	$ 91,605
Building and Building Improvements [Member] | Minimum [Member]
REAL ESTATE AND ACCUMULATED DEPRECIATION
Estimated useful lives of assets	10 years
Building and Building Improvements [Member] | Maximum [Member]
REAL ESTATE AND ACCUMULATED DEPRECIATION
Estimated useful lives of assets	45 years
Equipment Tenant Improvements and Fixtures [Member] | Minimum [Member]
REAL ESTATE AND ACCUMULATED DEPRECIATION
Estimated useful lives of assets	5 years
Equipment Tenant Improvements and Fixtures [Member] | Maximum [Member]
REAL ESTATE AND ACCUMULATED DEPRECIATION
Estimated useful lives of assets	10 years
Computer, Hardware and Software and Vehicles [Member] | Minimum [Member]
REAL ESTATE AND ACCUMULATED DEPRECIATION
Estimated useful lives of assets	3 years
Computer, Hardware and Software and Vehicles [Member] | Maximum [Member]
REAL ESTATE AND ACCUMULATED DEPRECIATION
Estimated useful lives of assets	5 years