CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) $ in Thousands		4 Months Ended	5 Months Ended	12 Months Ended
		Jul. 31, 2017	Dec. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Revenues:
Total revenues		$ 151,369	$ 178,753	$ 486,549	$ 406,520
Costs and expenses:
Vessel operating costs		116,438	120,502	329,196	269,580
Costs of other operating revenues		2,348	3,792	2,800	5,530
General and administrative		41,832	46,619	103,716	110,023
Vessel operating leases		6,165	1,215
Depreciation and amortization		47,447	20,337	101,931	58,293
Gain on asset dispositions, net		(3,561)	(6,616)	(2,263)	(10,624)
Impairment of due from affiliate					20,083
Long-lived asset impairments and other		184,748	16,777	37,773	61,132
Total costs and expenses		395,417	202,626	573,153	514,017
Operating loss		(244,048)	(23,873)	(86,604)	(107,497)
Other income (expense):
Foreign exchange gain (loss)		(3,181)	(407)	(1,269)	106
Equity in net earnings (losses) of unconsolidated companies		4,786	2,130	(3,152)	(18,864)
Interest income and other, net		2,384	2,771	6,598	11,294
Reorganization items		(1,396,905)	(4,299)
Loss on early extinguishment of debt					(8,119)
Interest and other debt costs, net		(11,179)	(13,009)	(29,068)	(30,439)
Total other income (expenses)		(1,404,095)	(12,814)	(26,891)	(46,022)
Loss before income taxes		(1,648,143)	(36,687)	(113,495)	(153,519)
Income tax (benefit) expense		(1,234)	2,039	27,724	18,252
Net loss		(1,646,909)	(38,726)	(141,219)	(171,771)
Less: Net income (losses) attributable to noncontrolling interests			540	524	(254)
Net loss attributable to Tidewater Inc.		$ (1,646,909)	$ (39,266)	$ (141,743)	$ (171,517)
Basic loss per common share		$ (34.95)	$ (1.82)	$ (3.71)	$ (6.45)
Diluted loss per common share		$ (34.95)	$ (1.82)	$ (3.71)	$ (6.45)
Weighted average common shares outstanding	[1]	47,121,330	21,539,143	38,204,934	26,589,883
Adjusted weighted average common shares		47,121,330	21,539,143	38,204,934	26,589,883
Vessel Revenues
Revenues:
Total revenues		$ 146,597	$ 171,884	$ 477,015	$ 397,206
Other Operating Revenues
Revenues:
Total revenues		$ 4,772	$ 6,869	$ 9,534	$ 9,314

[1] Basic weighted average shares outstanding included 924,125 shares issuable upon the exercise of New Creditor Warrants held by U.S. citizens at December 31, 2017 (Successor).