Debt - $105 Million Secured Mortgage Notes Assumed (Narrative) (Details) $ in Thousands		1 Months Ended	12 Months Ended
	May 10, 2016 a	Nov. 30, 2011 USD ($) a	Dec. 31, 2016 USD ($) a	Dec. 31, 2015 USD ($) a
Debt Instrument [Line Items]
Acres acquired | a	61,000	250,000	110,727	36,750
Carrying value of debt			$ 1,065,472	$ 833,879
Mortgage notes due 2017 at fixed interest rates of 4.35%
Debt Instrument [Line Items]
Noncash or part noncash acquisition, debt assumed		$ 105,000
Fixed interest rate		4.35%	4.35%
Debt instrument term, years		7 years
Repayments of secured debt		$ 21,000	$ 10,500
Carrying value of debt			31,676	$ 42,638
Outstanding principal			$ 31,500