Employee Retirement Plans - Additional Information (Detail) kr in Millions				1 Months Ended		9 Months Ended	12 Months Ended
	Jan. 02, 2016	Dec. 31, 2015	Dec. 01, 2015	Apr. 30, 2018 USD ($)	Dec. 31, 2010 Person	Dec. 31, 2017 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2019 NOK (kr)	Dec. 31, 2018 USD ($) Person	Dec. 31, 2018 NOK (kr) Person	Dec. 31, 2017 USD ($)	Dec. 31, 2017 NOK (kr)	Mar. 31, 2017 USD ($)	Mar. 31, 2017 NOK (kr)	Jan. 01, 2019 USD ($)
Defined Benefit Plan Disclosure [Line Items]
Number of employers participated in defined benefit plan | Person					60
Number of employers still remains in defined benefit plan | Person									20	20
Cash and cash equivalents						$ 432,035,000			$ 371,791,000		$ 432,035,000
Defined benefit plan, significant concentrations of risk									U.S. Plans The pension plan assets are periodically evaluated for concentration risks. As of December 31, 2018, we did not have any individual asset investments that comprised 10% or more of each plan’s overall assets.	U.S. Plans The pension plan assets are periodically evaluated for concentration risks. As of December 31, 2018, we did not have any individual asset investments that comprised 10% or more of each plan’s overall assets.
Defined benefit plan, concentration risk, assets, equity securities, difference plan assets and liabilities									15.00%	15.00%
Defined benefit plan, concentration risk, assets, equity securities, maximum foreign and us stock									10.00%	10.00%
Unrecognized actuarial (loss) gain									$ 0
Unrecognized prior service credit (cost)									$ 0
Defined contribution plan, description									Effective January 1, 2018, we no longer provides a matching of 50% of the first 8% of eligible compensation in an attempt to reduce costs.	Effective January 1, 2018, we no longer provides a matching of 50% of the first 8% of eligible compensation in an attempt to reduce costs.
Retirement Contributions
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, company contribution percentage									3.00%	3.00%
Defined contribution plan, company contribution, vesting period, years									5 years	5 years
Retirement Contributions | Minimum
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, company contribution percentage additional percentage									1.00%	1.00%
Retirement Contributions | Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, company contribution percentage additional percentage									8.00%	8.00%
Defined Contribution Savings Plan 401k
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, company contribution, vesting period, years									5 years	5 years
Percentage of defined plan, minimum employee contribution									2.00%
Percentage of defined plan, maximum employee contribution									75.00%
Percentage of defined plan, company contribution match, cash	50.00%
Percentage of defined plan, company contribution match, employee deferred compensation	8.00%	8.00%
Defined contribution plan, company contribution percentage match, company stock		50.00%
Non-Qualified Supplemental Savings Plan Executives
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, company contribution percentage match, common stock									50.00%	50.00%
Deferred compensation arrangement with individual, deferred compensation percentage									50.00%	50.00%
Deferred compensation arrangement with individual, deferred bonus percentage									100.00%	100.00%
Defined contribution plan, restoration benefit									3.00%	3.00%
Non-Qualified Supplemental Savings Plan Executives | Minimum
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, company contribution percentage additional percentage									1.00%	1.00%
Non-Qualified Supplemental Savings Plan Executives | Maximum
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, company contribution percentage additional percentage									8.00%	8.00%
Multinational Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, company contribution, vesting period, years			5 years
Percentage of defined plan, minimum employee contribution			1.00%
Percentage of defined plan, maximum employee contribution			50.00%
Percentage of defined plan, company contribution match, cash			50.00%
Percentage of defined plan, company contribution match, employee deferred compensation			6.00%
Norway?s Defined Benefit Pension Plan
Defined Benefit Plan Disclosure [Line Items]
Number of employers still remains in defined benefit plan | Person									175	175
Defined benefit plan, employer contributions									$ 200,000	kr 1.9	$ 300,000	kr 2.7	$ 400,000	kr 3.6
Norway?s Defined Benefit Pension Plan | Scenario Forecast
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, employer contributions							$ 500,000	kr 4.3
Norway?s Defined Benefit Pension Plan | GulfMark
Defined Benefit Plan Disclosure [Line Items]
Number of employers still remains in defined benefit plan | Person									106	106
Merchant Navy Officers Pension Fund
Defined Benefit Plan Disclosure [Line Items]
Multi-employer retirement fund accrued liability									$ 800,000
Merchant Navy Ratings Pension Fund
Defined Benefit Plan Disclosure [Line Items]
Multi-employer retirement fund accrued liability									600,000
Multi-employer retirement fund expected accrued liability									200,000
Pension Plans, Defined Benefit
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, employer contributions						0			0				3,000,000
Supplemental Executive Retirement Plan
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, employer contributions						$ 100,000			900,000				200,000
Cash and cash equivalents									18,000
Supplemental Executive Retirement Plan | President, and Chief Executive Officer
Defined Benefit Plan Disclosure [Line Items]
Settlement of distribution				$ 8,900,000
Settlement loss				$ (300,000)
Postretirement Benefit Plan
Defined Benefit Plan Disclosure [Line Items]
Postretirement benefit plan obligations reduction									$ 1,900,000
Additional estimated net periodic benefit													$ 2,000,000
Postretirement Benefit Plan | Subsequent Event
Defined Benefit Plan Disclosure [Line Items]
Gain on termination of post retirement benefit plan															$ 4,000,000