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Employee Benefit Plans - Additional Information (Detail) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]      
Provision for contributions to the Supplemental Plan $ 0.1 $ 0.1 $ 0.1
US Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Employers percentage matching of first 5% of each employee's qualifying annual compensation 100.00% 100.00% 100.00%
Defined Contribution Plan, Matching Contribution per employee by the company 5.00% 5.00% 5.00%
Defined contribution plan, cost recognized $ 9.1 $ 8.0 $ 8.9
UK Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined contribution plan, cost recognized $ 2.1 $ 1.5 $ 1.4
UK Plan [Member] | U. K. Sector of North Sea [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Contribution Plan, Matching Contribution by the company 6.00% 6.00% 6.00%
International Savings Plan [Member]      
Defined Benefit Plan Disclosure [Line Items]      
Defined Contribution Plan, Matching Contribution per employee by the company 5.00% 5.00% 5.00%
Defined contribution plan, cost recognized $ 0.4 $ 0.4 $ 0.4