Interest and Debt Expense - Details of Interest and Debt Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Interest And Debt Expense [Abstract]
Interest expense	$ 32,914	$ 36,820	$ 99,201	$ 109,285
Amortization of deferred financing costs	2,819	1,458	8,367	4,121
Total interest and debt expense	$ 35,733	$ 38,278	$ 107,568	$ 113,406