Commitments and Contingencies (Details) R$ in Millions, $ in Millions, ₩ in Billions	3 Months Ended				12 Months Ended
	Jun. 30, 2017 USD ($)	Jun. 30, 2017 KRW (₩)	Dec. 31, 2016 USD ($)	Dec. 31, 2016 KRW (₩)	Dec. 31, 2017 USD ($)	Dec. 31, 2017 KRW (₩)	Mar. 31, 2021 USD ($)	Mar. 31, 2021 BRL (R$)
Tax Authority, South Korea (SRTO) | Assessment
Loss Contingencies [Line Items]
Pre-assessment notice, amount				₩ 11.7
Tax Authority, South Korea (SRTO) | Assessment | Foreign Tax Authority
Loss Contingencies [Line Items]
Pre-assessment notice, amount			$ 10.4		$ 10.0	₩ 11.3
Tax Authority, South Korea (SRTO) | Additional Assessment
Loss Contingencies [Line Items]
Pre-assessment notice, amount	$ 17.8	₩ 20.1
Federal, State and Municipal Tax Authorities in Brazil | Assessment
Loss Contingencies [Line Items]
Estimate of possible loss							$ 9.9	R$ 57.3