Schedule III - Real Estate and Accumulated Depreciation - Activity in Real Estate Facilities (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Real estate, gross:
Balance at beginning of year	$ 6,392,487
Balance at end of year	7,649,448	$ 6,392,487
Accumulated depreciation:
Balance at beginning of year	728,087
Balance at end of year	900,861	728,087
Net real estate assets:
Net real estate assets	6,770,447	5,689,309	$ 4,135,696
Aggregate cost of real estate for U.S. federal income tax purposes	6,513,574
Operating Facilities [Member]
Real estate, gross:
Balance at beginning of year	6,392,487	4,722,162	4,126,648
Acquisitions	1,159,304	1,609,608	557,158
Improvements	92,480	46,696	32,861
Transfers from construction in progress (to operating facilities)	26,400	19,971	12,308
Dispositions and other	(21,223)	(5,950)	(6,813)
Balance at end of year	7,649,448	6,392,487	4,722,162
Accumulated depreciation:
Balance at beginning of year	728,087	604,336	496,754
Depreciation expense	174,906	123,751	109,531
Dispositions and other	(2,132)	0	(1,949)
Balance at end of year	900,861	728,087	604,336
Real Estate Under Development/Redevelopment [Member]
Real estate, gross:
Balance at beginning of year	24,909	17,870	6,650
Current development	23,404	27,010	23,528
Transfers from construction in progress (to operating facilities)	(26,400)	(19,971)	(12,308)
Dispositions and other	(53)	0	0
Balance at end of year	$ 21,860	$ 24,909	$ 17,870