Lease - Maturity of lease liabilities (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2019	Dec. 31, 2018
Operating Leases
2019	$ 43,544
2020	54,611
2021	51,209
2022	42,355
2023	19,226
Thereafter	33,057
Total lease payments	244,002
Less imputed interest	(24,081)
Total	219,921
Finance Leases
2019	5,581
2020	7,406
2021	7,161
2022	7,127
2023	6,732
Thereafter	6,936
Total lease payments	40,943
Less imputed interest	(4,840)
Total	36,103
Operating Leases.
2019		$ 54,818
2020		54,738
2021		50,794
2022		42,048
2023		19,089
Thereafter		32,894
Total		254,381
Finance Leases
2019		7,393
2020		7,319
2021		7,085
2022		7,051
2023		6,658
Thereafter		6,868
Total lease payments		42,374
Less imputed interest		(5,197)
Total		$ 37,177
Operating And Finance Leases	$ 2,200