Commitments and Contingencies - Finance Leases (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Total Payments of future minimum lease payments
Remainder of 2019	$ 22,864
2020	29,208
2021	24,247
2022	16,419
2023	13,866
2024 and thereafter	31,035
Total future minimum lease payments	137,639
Less imputed lease interest	(38,070)
Total lease liabilities	135,192
Finance lease costs
Right of use assets obtained in exchange for new finance lease liabilities	0	$ 300
Restricted Cash
Restricted cash	34,300
Letter of credit	35,100
Sale Leaseback Agreements
Total Payments of future minimum lease payments
Total lease liabilities	29,900
Finance lease costs
Amortization of right of use asset	808	1,624
Interest on finance obligations	2,091	1,510
Total finance lease cost	2,899	3,134
Other information
Cash payments	$ 54,170	$ 9,390
Weighted average remaining lease term (years)	3 years 6 months 11 days	3 years 10 months 24 days
Weighted average discount rate	10.80%	9.60%
Finance Lease [Member]
Total Payments of future minimum lease payments
Remainder of 2019	$ 5,041
2020	6,722
2021	6,722
2022	4,975
2023	3,175
2024 and thereafter	16,154
Total future minimum lease payments	42,789
Less imputed lease interest	(12,898)
Sale of future services	35,623
Total lease liabilities	65,514
Other Leased Property [Member]
Total Payments of future minimum lease payments
Remainder of 2019	325
2020	418
2021	391
2022	374
2023	363
2024 and thereafter	1,528
Total future minimum lease payments	3,399
Less imputed lease interest	(1,022)
Total lease liabilities	2,377
Finance obligation
Restricted Cash
Letter of credit	500
Finance obligation | Property and equipment
Total Payments of future minimum lease payments
Total future minimum lease payments	$ 2,400