Schedule III Real Estate and Accumulated Depreciation - Rollforwards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Property
Balance, beginning of year	$ 1,295,135	$ 1,146,548	$ 1,048,525
Additions - property acquisitions	58,149
Additions - improvements	290,292	148,587	98,969
Deduction - cost of land disposal			(946)
Balance, end of year	1,643,576	1,295,135	1,146,548
Accumulated Depreciation
Balance, beginning of year	284,219	215,978	155,704
Additions, net of disposals	85,084	68,241	60,274
Balance, end of year	$ 369,303	$ 284,219	$ 215,978