Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Tax Disclosure [Abstract]
Investments and property, primarily differences in investment basis, depreciation and amortization, the basis of land assets, and the treatment of interests and certain costs	$ 31,691	$ 28,940	$ 19,862
Net operating loss carryforward	10,720	8,784	3,703
Expense accruals and other	229	(847)	(753)
Valuation allowance	(548)	(606)	(531)
Net deferred tax assets	$ 42,092	$ 36,271	$ 22,281