Supplemental Cash Flow Information (Details) - USD ($) $ in Thousands	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Property and equipment acquired under capital lease	$ 216	$ 3,092
Property and equipment in payables	$ 3,643	$ 4,512
Class A Common Stock
Number of common stock shares issued upon redemption of CW units	8,517,733
Class B Common Stock
Economic interest of shares	$ 0

Future cash outflow to pay for purchases of fixed assets that have occurred.

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The increase during the period in capital lease obligations due to entering into new capital leases.

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