Leases - Leases Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Assets:
Operating lease assets	$ 871,746	$ 0
Finance lease assets	55,073
Total leased assets	926,819
Current
Operating	91,919
Finance	4,838
Non-current
Operating	800,828
Finance	53,820
Total lease liabilities	$ 951,405