Leases - Operating Lease Assets and Liabilities (Details) - USD ($) $ in Thousands	Sep. 30, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	$ 10,892	$ 23,006
Current portion of operating lease liabilities	10,109	22,045
Noncurrent portion of operating lease liabilities	2,766	3,173
Chartered In Contracts
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	8,375	19,116
Current portion of operating lease liabilities	9,497	21,328
Noncurrent portion of operating lease liabilities	$ 0	$ 0
Weighted average remaining lease term (in years)	7 months 6 days	7 months 6 days
Weighted average discount rate	6.60%	6.00%
Office leases
Lessee, Lease, Description [Line Items]
Operating lease right-of-use assets	$ 2,517	$ 3,890
Current portion of operating lease liabilities	612	717
Noncurrent portion of operating lease liabilities	$ 2,766	$ 3,173
Weighted average remaining lease term (in years)	4 years 7 months 6 days	4 years 8 months 12 days
Weighted average discount rate	7.10%	6.90%