Leases - Lease Assets and Liabilities (Details) - USD ($) $ in Thousands	Jun. 30, 2019	Jan. 01, 2019
Right-of-use assets:
Operating	$ 113,643	$ 120,358
Finance	544,565
Total right-of-use assets	658,208
Current:
Operating	16,181
Finance	42,682
Noncurrent:
Operating	94,979	$ 100,085
Finance	166,225
Total lease liabilities	320,067
Finance lease accumulated amortization	$ 511,000