Notes Payable, Revolving Credit Facility, Interest and Amortization of Deferred Debt Costs - Interest Expense and Amortization of Deferred Debt Costs (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Debt Disclosure [Abstract]
Interest incurred	$ 12,881	$ 12,200
Amortization of deferred debt costs	384	470
Capitalized interest	(2,146)	(1,144)
Interest expense	11,119	11,526
Less: Interest income	52	102
Interest expense, net	$ 11,067	$ 11,424