Consolidated Statements Of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Cash flows from operating activities:
Net income (loss)	$ (87,784)	$ (61,684)	$ 20,084
Adjustments to reconcile net income (loss) to net cash provided by operating activities:
Depreciation and amortization	142,686	141,514	133,709
Goodwill impairment			6,689
Amortization of debt discounts			6,964
Amortization of debt issuance costs	2,334	3,179	3,177
Share-based compensation	7,451	7,689	8,568
Deferred income taxes	4,386	(15,202)	(3,883)
Equity in (earnings) losses of investment	(8,262)	1	(216)
(Gain) loss on disposition of assets, net		631	(889)
(Gain) loss on extinguishment of long-term debt		136	(9,239)
Unrealized gain on derivative contracts, net			(601)
Unrealized foreign currency (gain) loss	21,596	2,252	(2,665)
Change in fair value of contingent consideration	16,054
Changes in operating assets and liabilities:
Accounts receivable, net	(29,865)	(14,154)	(8,419)
Other current assets	7,593	22,973	(28,664)
Income tax payable, net of income tax receivable	(49)	18,610	(22,124)
Accounts payable and accrued liabilities	9,807	46,645	10,830
Deferred recertification and dry dock costs, net	(35,072)	(9,620)	(19,348)
Other, net	(233)	2,853	(4,827)
Net cash provided by operating activities	51,108	140,117	98,800
Cash flows from investing activities:
Alliance acquisition, net of cash acquired	(112,625)
Capital expenditures	(33,504)	(8,322)	(20,244)
Distribution from equity investment, net	7,840
Proceeds from sale of assets		51	963
Net cash used in investing activities	(138,289)	(8,271)	(19,281)
Cash flows from financing activities:
Proceeds from convertible senior notes			200,000
Repayment of convertible senior notes	(35,000)		(183,150)
Capped call transactions			(10,625)
Debt issuance costs	(580)	(1,337)	(7,747)
Acquisition of redeemable noncontrolling interests		(2,355)
Payments related to tax withholding for share-based compensation	(1,902)	(2,001)	(5,264)
Proceeds from issuance of ESPP shares	575	654	622
Net cash used in financing activities	(44,844)	(95,997)	(52,578)
Effect of exchange rate changes on cash and cash equivalents and restricted cash	(5,991)	(42)	1,818
Net increase (decrease) in cash and cash equivalents and restricted cash	(138,016)	35,807	28,759
Cash and cash equivalents and restricted cash:
Balance, beginning of year	327,127	291,320	262,561
Balance, end of year	189,111	327,127	291,320
Term Loan Repaid September 2021
Cash flows from financing activities:
Repayment of loan debt		(29,826)	(3,500)
Nordea Q5000 Loan Matured January 2021
Cash flows from financing activities:
Repayment of loan debt		(53,572)	(35,714)
MARAD Debt (matures February 2027)
Cash flows from financing activities:
Repayment of loan debt	$ (7,937)	$ (7,560)	$ (7,200)