Leases - Balance Sheet Classification of Lease Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019	Dec. 31, 2018
Leases [Abstract]
Property and equipment, net	$ 461,549		$ 640,952
Total finance lease assets	461,549		640,952
Capital lease obligations, current portion			9,817
Other current liabilities	37,047		5,271
Capital lease obligations, excluding current portion			19,658
Construction financing lease obligation, excluding current portion			561,892
Long-term finance lease liabilities	551,530	$ 569,487
Total finance lease liabilities	588,577		$ 596,638
Operating lease assets	58,031	61,674
Other current liabilities	7,941
Long-term operating lease liabilities	60,433	$ 64,849
Total operating lease liabilities	$ 68,374