Schedule III - Real Estate and Accumulated Depreciation Schedule III - Real Estate and Accumulated Depreciation (Summary) (Details) (Details) - USD ($)	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
SEC Schedule III, Real Estate and Accumulated Depreciation [Line Items]
SEC Schedule III, Real Estate, Gross, January 1	$ 1,988,849,000	$ 1,422,002,000	$ 698,536,000
Payments to Acquire Property, Plant, and Equipment	124,113,000	533,171,000	654,670,000
Change In Accounts Payable, Real Property Additions	1,076,000	(995,000)	3,086,000
Additions Through Contingent Liabilities	750,000	3,000,000	1,600,000
Additions Through Assumption Of Debt	0	7,858,000	80,528,000
Payments for Delayed Tax Exempt Exchange	0	23,813,000	0
Settlement of Contingent Asset Acquisition Liability	(3,000,000)	0	0	$ 0
Settlement Of Mortgage Note By Real Estate Acquisition	0	0	13,741,000
Additions Through Settlement Of Mortgage Note	255,000	0	0
SEC Schedule III, Real Estate, Cost of Real Estate Sold	(13,563,000)	0	(30,159,000)
SEC Schedule III, Real Estate, Other Deductions	2,614,000	0	0
SEC Schedule III, Real Estate, Gross, December 31	2,095,866,000	1,988,849,000	1,422,002,000	698,536,000
SEC Schedule III, Real Estate Accumulated Depreciation, January 1	212,300,000	174,262,000	163,146,000
SEC Schedule III, Real Estate Accumulated Depreciation, Depreciation Expense	53,123,000	38,038,000	20,658,000
SEC Schedule III, Real Estate Accumulated Depreciation, Real Estate Sold	(5,096,000)	0	(9,542,000)
SEC Schedule III, Real Estate Accumulated Depreciation, Other Deductions	1,268,000	0	0
SEC Schedule III, Real Estate Accumulated Depreciation, December 31	$ 259,059,000	$ 212,300,000	$ 174,262,000	$ 163,146,000