Basis of Presentation and Significant Accounting Policies - Additional Information (Details)	6 Months Ended	9 Months Ended
	Sep. 30, 2019 USD ($)	Sep. 30, 2020 USD ($) lease numberOfVessel	Dec. 31, 2019 USD ($)
Property, Plant and Equipment [Line Items]
Restricted cash	$ 2,500,000	$ 2,500,000	$ 2,500,000
Restricted cash		$ 1,500,000	1,000,000
Number of vessels chartered to customers | numberOfVessel		9
Lease payments		$ 3,381,000
Time charter, term to completion	15 years	56 days
Number of noncancelable office leases | lease		2
Bulk Nordic Odin, Bulk Nordic Olympic, Bulk Nordic Odyssey, Bulk Nordic Orion and Bulk Nordic Oshima Loan Agreement
Property, Plant and Equipment [Line Items]
Restricted cash		$ 2,500,000	$ 2,500,000
Restricted cash		$ 1,500,000
Minimum
Property, Plant and Equipment [Line Items]
Vessel lease term		26 days
Maximum
Property, Plant and Equipment [Line Items]
Vessel lease term		60 days