Accrued Expenses and Other Current Liabilities and Other Liabilities - Other liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Accrued Expenses and Other Current Liabilities and Other Liabilities
Supplemental executive retirement plan obligations	$ 18,865		$ 20,195
Derivative liability	11,078		3,134
Long-term insurance accruals	8,393		8,713
Unrecognized tax benefits, and related interest and penalties	5,407		5,458
Deferred tenant improvement allowances			8,570
Deferred rent			4,455
Other	2,290		1,045
Total other liabilities	$ 46,033	$ 38,620	$ 51,570