Other Assets and Accrued Liabilities - Current Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Jan. 01, 2019	Dec. 31, 2018
Other Liabilities Disclosure [Abstract]
Sales and property taxes payable	$ 4,937		$ 4,281
Asset retirement obligations	524		582
Accrued programming costs	3,083		2,886
Financing leases	86
Other current liabilities	6,499		6,814
Accrued liabilities and other	$ 15,129	$ 14,151	$ 14,563