Leases - Lease Liability Maturity (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Operating leases
2019	$ 17,322
2020	18,962
2021	15,817
2022	13,923
2023	13,341
After 2023	75,274
Total lease payments	154,639
Less interest	(41,972)
Present value of lease liabilities	112,667
Finance leases
2019	47,400
2020	63,266
2021	59,692
2022	41,040
2023	40,942
After 2023	30,707
Total lease payments	283,047
Less interest	(64,102)
Present value of lease liabilities	218,945
Total
2019	64,722
2020	82,228
2021	75,509
2022	54,963
2023	54,283
After 2023	105,981
Total lease payments	437,686
Less interest	(106,074)
Total lease liabilities	$ 331,612
Future Minimum Rental Payments Under Non-Cancelable Operating Leases
2019		$ 21,146
2020		18,081
2021		13,873
2022		10,118
2023		8,814
Thereafter		21,886
Total		$ 93,918