Leased Properties - Future Lease Payments (Details) $ in Thousands	Jun. 30, 2019 USD ($)
Leases [Abstract]
July 1, 2019 through December 31, 2019	$ 144,705
2020	263,440
2021	200,553
2022	147,423
2023	101,241
Thereafter	219,101
Total undiscounted future minimum lease payments	1,076,463
Less: Difference between undiscounted lease payments and discounted operating lease liabilities	128,411
Total operating lease liabilities	$ 948,052