Vessels - Additional Information (Details)	3 Months Ended	6 Months Ended
	Jun. 30, 2021 USD ($) vessel bank shares	Jun. 30, 2021 USD ($) vessel bank	Jun. 30, 2020 USD ($)	Jun. 01, 2021 USD ($)	Mar. 31, 2021 USD ($) vessel shares	Dec. 31, 2020 USD ($) vessel	Sep. 30, 2018 USD ($) vessel
Property, Plant and Equipment [Line Items]
Number of vessels | vessel	51	51
Number of vessels acquired | vessel					4
Fair value of warrants issued as consideration for vessels purchase	$ 8,400,000	$ 8,400,000
Issuance of shares upon conversion of warrants (in shares) | shares	432,037
Additional common stock issued upon delivery | shares	109,861
Amount recorded in balance sheet		$ 5,340,000	$ 0
Warrants Issued For Consideration
Property, Plant and Equipment [Line Items]
Warrant for common stock (in shares) | shares					541,898
Fair value of warrants issued as consideration for vessels purchase					$ 10,700,000
High-Specification Scrubber-Fitted Ultramax Bulkcarriers
Property, Plant and Equipment [Line Items]
Number of vessels acquired | vessel	2	2				3
Vessel purchase price	$ 44,000,000.0	$ 44,000,000.0			$ 15,000,000.0	$ 50,200,000
High-Specification Scrubber-Fitted Ultramax Bulkcarriers | Warrants Issued For Consideration
Property, Plant and Equipment [Line Items]
Warrant for common stock (in shares) | shares					212,315
Crown-58 Supramax Bulkcarriers
Property, Plant and Equipment [Line Items]
Number of vessels acquired | vessel					3
Vessel purchase price					$ 21,200,000
Number of vessels delivered | vessel	3	3
Crown-58 Supramax Bulkcarriers | Warrants Issued For Consideration
Property, Plant and Equipment [Line Items]
Warrant for common stock (in shares) | shares					329,583
Ballast Water Treatment System
Property, Plant and Equipment [Line Items]
Number of vessels | vessel							39
Amount recorded in balance sheet		$ 7,800,000
Projected project costs							$ 500,000
Number of vessels, installation completed | bank	16	16
Scrubbers and BWTS reclassified		$ 4,000,000.0
Vessels and Vessel Improvements
Property, Plant and Equipment [Line Items]
Vessel held for sale		4,885,998
Amount recorded in balance sheet		3,250,000
Scrubbers and BWTS reclassified		$ 802,369
Vessel Tern
Property, Plant and Equipment [Line Items]
Total consideration for vessel purchase				$ 9,700,000