Leases - Maturities Of Operating Lease Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2020	Dec. 31, 2019
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Remainder of 2020	$ 48,935
2020		$ 66,820
2021	59,814	60,452
2022	57,215	57,363
2023	39,145	39,202
2024	6,769	6,819
Thereafter	5,954	6,251
Total lease payments	217,832	236,907
Less: imputed interest	(27,358)	(31,295)
Total operating lease liabilities	190,474	205,612
Current operating lease liabilities	53,063	53,785
Non-current operating lease liabilities	137,411	151,827
Vessels
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Remainder of 2020	44,316
2020		60,210
2021	54,184	54,564
2022	52,106	52,106
2023	34,580	34,580
2024	2,470	2,470
Thereafter	0	0
Total lease payments	187,656	203,930
Less: imputed interest	(21,611)	(24,846)
Total operating lease liabilities	166,045	179,084
Current operating lease liabilities	48,296	48,716
Non-current operating lease liabilities	117,749	130,368
Facilities and Equipment
Lessee, Operating Lease, Liability, Payment, Due [Abstract]
Remainder of 2020	4,619
2020		6,610
2021	5,630	5,888
2022	5,109	5,257
2023	4,565	4,622
2024	4,299	4,349
Thereafter	5,954	6,251
Total lease payments	30,176	32,977
Less: imputed interest	(5,747)	(6,449)
Total operating lease liabilities	24,429	26,528
Current operating lease liabilities	4,767	5,069
Non-current operating lease liabilities	$ 19,662	$ 21,459