Debt - Convertible Bond Debt (Details)			9 Months Ended
	Sep. 15, 2020	Jul. 29, 2019 USD ($) vessel	Sep. 30, 2023 USD ($) $ / shares shares	Jun. 30, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Sep. 30, 2022 USD ($)	Jun. 30, 2022 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Debt Instrument [Line Items]
Net proceeds		$ 112,500,000
Number of vessels acquired | vessel		6
Conversion premium per principal amount of notes		$ 1,000	$ 1,000
Stockholders' equity attributable to parent			598,072,000	$ 608,757,000	$ 811,709,000	$ 819,181,000	$ 819,203,000	$ 765,495,000	$ 693,769,000	$ 671,266,000
Debt discounts and debt issuance costs			(9,047,000)			(7,387,000)
Accumulated Deficit
Debt Instrument [Line Items]
Stockholders' equity attributable to parent			(162,418,000)	(151,697,000)	(168,373,000)	(163,556,000)	(162,712,000)	(210,854,000)	(278,858,000)	(313,495,000)
Additional Paid-in Capital
Debt Instrument [Line Items]
Stockholders' equity attributable to parent			$ 746,898,000	$ 745,636,000	$ 966,261,000	966,058,000	$ 964,494,000	$ 963,482,000	$ 961,930,000	982,746,000
Cumulative effect of adoption of ASU 2020-06
Debt Instrument [Line Items]
Stockholders' equity attributable to parent										(12,050,000)
Cumulative effect of adoption of ASU 2020-06 | Accumulated Deficit
Debt Instrument [Line Items]
Stockholders' equity attributable to parent										8,676,000
Cumulative effect of adoption of ASU 2020-06 | Additional Paid-in Capital
Debt Instrument [Line Items]
Stockholders' equity attributable to parent										(20,726,000)
Cumulative effect of adoption of ASU 2020-06 | Accounting Standards Update 2020-06 | Accumulated Deficit
Debt Instrument [Line Items]
Stockholders' equity attributable to parent										8,700,000
Cumulative effect of adoption of ASU 2020-06 | Accounting Standards Update 2020-06 | Additional Paid-in Capital
Debt Instrument [Line Items]
Stockholders' equity attributable to parent										20,700,000
Convertible Bond Debt
Debt Instrument [Line Items]
Debt instrument, face amount		$ 114,100,000
Range of interest rates		5.00%
Debt issuance costs		$ 1,600,000
Conversion premium (in shares) | shares			31.5446
Conversion price (in dollars per share) | $ / shares			$ 31.70
Reverse stock split ratio	0.1
Debt discounts and debt issuance costs			$ (328,000)			$ (620,000)
Convertible Bond Debt | Accounting Standards Update 2020-06
Debt Instrument [Line Items]
Debt discounts and debt issuance costs										$ 12,000,000
Convertible Bond Debt | Debt Instrument, Redemption, Period Two
Debt Instrument [Line Items]
Redemption price percentage		100.00%
Convertible Bond Debt | Other Liabilities
Debt Instrument [Line Items]
Debt issuance costs		$ 1,000,000
Unsecured Debt
Debt Instrument [Line Items]
Amount of principal amount eligible for declaration in case of default		25.00%
Amount of notes to be due and payable		100.00%