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		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Debt Disclosure [Abstract]
Interest incurred	$ 12,988	$ 12,302	$ 25,868	$ 24,503
Amortization of deferred debt costs	375	377	760	847
Capitalized interest	(2,522)	(1,442)	(4,668)	(2,586)
Interest expense	10,841	11,237	21,960	22,764
Less: Interest income	48	69	100	170
Interest expense, net and amortization of deferred debt costs	$ 10,793	$ 11,168	$ 21,860	$ 22,594