Note 13 - Segment and Geographic Distribution of Operations - Segment Reporting Information (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022	Dec. 31, 2022
Revenue	$ 214,961	$ 163,447	$ 408,065	$ 269,176
Corporate expenses	176,014	161,607	344,619	274,646
Long-lived asset impairment credit	0	0	0	500
Gain on asset dispositions, net	1,404	(1,297)	3,620	(1,090)
Operating income (loss)	38,947	1,840	63,446	(5,470)
Depreciation and amortization	32,768	31,766	63,434	58,423
Property Plant And Equipment Additions	21,020	4,151	29,671	5,380
Total Assets	1,344,164		1,344,164		$ 1,297,656
Vessel [Member]
Revenue	210,323	162,175	401,503	266,051
Product and Service, Other [Member]
Revenue	4,638	1,272	6,562	3,125
Operating Segments [Member]
Revenue	214,961	163,447	408,065	269,176
Gross Profit	49,660	19,046	82,876	21,532
Operating Segments [Member] | Product and Service, Other [Member]
Revenue	4,638	1,272	6,562	3,125
Gross Profit	4,265	790	5,038	2,282
Operating Segments [Member] | Americas [Member]
Depreciation and amortization	8,724	7,503	16,918	14,619
Property Plant And Equipment Additions	1,040	538	1,561	538
Total Assets	307,964		307,964		309,985
Operating Segments [Member] | Americas [Member] | Vessel [Member]
Revenue	50,376	37,520	98,063	65,964
Gross Profit	6,245	5,930	14,207	5,848
Operating Segments [Member] | Asia Pacific [Member]
Depreciation and amortization	1,824	2,080	3,289	2,929
Property Plant And Equipment Additions	1,256	19	5,659	19
Total Assets	109,038		109,038		148,684
Operating Segments [Member] | Asia Pacific [Member] | Vessel [Member]
Revenue	22,585	16,362	44,609	21,259
Gross Profit	7,026	(899)	12,594	1,274
Operating Segments [Member] | Middle East [Member]
Depreciation and amortization	6,365	6,421	12,100	11,827
Property Plant And Equipment Additions	868	2,048	2,418	2,072
Total Assets	200,369		200,369		197,054
Operating Segments [Member] | Middle East [Member] | Vessel [Member]
Revenue	31,856	28,396	62,618	48,614
Gross Profit	(1,657)	(307)	(2,001)	(2,190)
Operating Segments [Member] | Europe and Mediterranean [Member]
Depreciation and amortization	7,445	6,958	14,795	13,720
Property Plant And Equipment Additions	1,948	169	2,180	445
Total Assets	278,660		278,660		282,670
Operating Segments [Member] | Europe and Mediterranean [Member] | Vessel [Member]
Revenue	39,295	32,475	70,545	56,394
Gross Profit	8,307	4,262	10,343	1,833
Operating Segments [Member] | West Africa [Member]
Depreciation and amortization	7,813	8,002	15,334	13,743
Property Plant And Equipment Additions	15,146	340	15,735	690
Total Assets	331,657		331,657		285,965
Operating Segments [Member] | West Africa [Member] | Vessel [Member]
Revenue	66,211	47,422	125,668	73,820
Gross Profit	25,474	9,270	42,695	12,485
Corporate, Non-Segment [Member]
Corporate expenses	(12,117)	(15,909)	(23,050)	(26,412)
Depreciation and amortization	597	802	998	1,585
Property Plant And Equipment Additions	762	$ 1,037	2,118	$ 1,616
Total Assets	$ 116,476		$ 116,476		$ 73,298