Employee Benefit Plans (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Contribution Plan Disclosure [Line Items]
Maximum percent of discretionary non-matching contributions by General Partner	2.00%
Expenses of the plan included in selling, general and administrative expenses	$ 3.5	$ 3.1	$ 3.0
Global 401(k) Plan
Defined Contribution Plan Disclosure [Line Items]
Maximum employee contribution as a percent of compensation	100.00%
Employee contribution subject to employer match, first level (as a percent)	100.00%
Employer contribution subject to employer match, second level (as a percent)	50.00%
GMG 401(k) Plan
Defined Contribution Plan Disclosure [Line Items]
Maximum employee contribution as a percent of compensation	100.00%
Employee contribution subject to employer match, first level (as a percent)	100.00%
Employer contribution subject to employer match, second level (as a percent)	50.00%
Maximum | Global 401(k) Plan
Defined Contribution Plan Disclosure [Line Items]
Employer match of first level of employee contribution (as a percent)	3.00%
Employer match of second level of employee contribution (as a percent)	5.00%
Maximum | GMG 401(k) Plan
Defined Contribution Plan Disclosure [Line Items]
Employer match of first level of employee contribution (as a percent)	3.00%
Employer match of second level of employee contribution (as a percent)	5.00%
Minimum | Global 401(k) Plan
Defined Contribution Plan Disclosure [Line Items]
Employer match of second level of employee contribution (as a percent)	3.00%
Minimum | GMG 401(k) Plan
Defined Contribution Plan Disclosure [Line Items]
Employer match of second level of employee contribution (as a percent)	3.00%