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		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Debt Disclosure [Abstract]
Interest incurred	$ 11,489	$ 11,415	$ 34,287	$ 33,998
Amortization of deferred debt costs	340	355	1,094	969
Capitalized interest	(600)	(186)	(1,393)	(430)
Interest expense and amortization of deferred debt costs	$ 11,229	$ 11,584	$ 33,988	$ 34,537