Leases - Operating Lease Assets and Liabilities (Details) - USD ($) $ in Thousands	Mar. 31, 2022	Dec. 31, 2021
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	$ 18,654	$ 17,017
Lease liabilities - short term	15,749	15,728
Lease liabilities - long term	$ 2,899	1,282
Minimum
Lessee, Lease, Description [Line Items]
Discount rate	1.33%
Maximum
Lessee, Lease, Description [Line Items]
Discount rate	6.08%
Weighted Average
Lessee, Lease, Description [Line Items]
Discount rate	2.88%
Chartered-in contracts greater than 12 months
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	$ 16,377	15,039
Lease liabilities - short term	14,966	15,039
Lease liabilities - long term	1,412	0
Office leases
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	2,277	1,978
Lease liabilities - short term	783	689
Lease liabilities - long term	$ 1,487	$ 1,282