Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Cash flows from operating activities:
Net income	$ 22,728	$ 248,009	$ 184,898
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation	46,522	47,911	44,862
Noncash operating lease expense	22,616	30,233	16,364
Amortization of deferred drydocking costs	13,999	13,244	8,656
Amortization of debt discount and debt issuance costs	2,738	2,130	7,083
Loss on debt extinguishment	0	4,169	6,085
Impairment of operating lease right-of-use assets	722	2,212	0
Gain on sale of vessels	(19,731)	(9,308)	(3,966)
Unrealized loss on derivative instruments, net	496	1,933	68
Stock-based compensation expense	7,492	6,108	3,481
Drydocking expenditures	(14,397)	(18,422)	(21,906)
Changes in operating assets and liabilities:
Accounts payable	1,364	(257)	10,067
Accounts receivable	1,384	(4,141)	(14,967)
Accrued interest	411	185	(1,733)
Inventories	3,092	(10,429)	(6,027)
Operating lease liabilities current and noncurrent	(24,732)	(30,227)	(17,132)
Collateral on derivatives	(1,310)	14,172	(15,081)
Fair value of derivatives, other current and noncurrent assets	36	(105)	(1,622)
Other accrued liabilities	(1,140)	4,452	6,205
Prepaid expenses	(994)	(1,170)	(179)
Unearned charter hire revenue	(5,359)	(2,416)	4,015
Net cash provided by operating activities	55,937	298,283	209,171
Cash flows from investing activities:
Purchase of vessels and vessel improvements	(82,355)	(27,676)	(128,254)
Advances for vessel purchases	0	(3,638)	0
Purchase of scrubbers and ballast water treatment systems	(2,648)	(7,307)	(6,712)
Proceeds from hull and machinery insurance claims	174	286	354
Net proceeds from sale of vessels	56,609	14,917	9,163
Purchase of other fixed assets	(900)	(274)	(33)
Net cash used in investing activities	(29,120)	(23,692)	(125,481)
Cash flows from financing activities:
Repurchase of Convertible Bond Debt	0	(14,181)	0
Debt issuance costs paid to lenders	0	(18)	(6,351)
Other financing costs	(103)	0	(731)
Repurchase of Common Stock and associated fees – related party (Note 9)	(222,889)	0	0
Proceeds from issuance of shares under ATM Offering, net of commissions	0	0	27,138
Proceeds from equity offerings, net of issuance costs	0	201
Payments on equity offerings, net of issuance costs			(493)
Cash paid for taxes related to net share settlement of equity awards	(2,297)	(2,355)	(1,937)
Cash used to settle fractional shares	0	0	0
Cash received from exercise of stock options	0	85	56
Dividends paid	(16,778)	(104,991)	(25,763)
Net cash used in financing activities	(95,381)	(171,059)	(86,317)
Net (decrease)/increase in cash, cash equivalents and restricted cash	(68,564)	103,532	(2,627)
Cash, cash equivalents and restricted cash at beginning of year	189,754	86,222	88,849
Cash, cash equivalents and restricted cash at end of year	121,190	189,754	86,222
Global Ultraco Debt Facility
Cash flows from financing activities:
Proceeds from debt	73,125	0	0
Proceeds from long-term lines of credit	123,361	0	0
Repayments of debt	(49,800)	(49,800)	(12,450)
Original Ultraco Debt Facility
Cash flows from financing activities:
Proceeds from debt	0	0	300,000
Proceeds from long-term lines of credit	0	0	50,000
Repayments of Long-term debt	0	0	(50,000)
New Ultraco Debt Facility
Cash flows from financing activities:
Proceeds from debt	0	0	16,500
Proceeds from long-term lines of credit	0	0	55,000
Repayments of debt	0	0	(182,930)
Repayments of Long-term debt	0	0	(55,000)
Norwegian Bond Debt
Cash flows from financing activities:
Repayments of Long-term debt	0	0	(184,356)
Super Senior Revolver Facility
Cash flows from financing activities:
Repayments of Long-term debt	0	0	(15,000)
Holdco Revolving Credit Facility
Cash flows from financing activities:
Proceeds from long-term lines of credit	0	0	24,000
Repayments of Long-term debt	$ 0	$ 0	$ (24,000)