Notes Payable - Interest Expense (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2019	Sep. 30, 2018	Sep. 30, 2019	Sep. 30, 2018
Interest Expense
Interest expense on debt and finance lease obligations	$ 11,406	$ 11,619	$ 34,399	$ 34,364
Noncash interest on derivatives and finance lease obligations, net	1,155	(818)	6,908	(4,995)
Amortization of deferred financing costs	698	748	2,094	2,240
Total interest expense	$ 13,259	$ 11,549	$ 43,401	$ 31,609