Annual report pursuant to Section 13 and 15(d)

Income Taxes - Open Tax Years by Major Tax Jurisdiction (Detail)

v3.6.0.2
Income Taxes - Open Tax Years by Major Tax Jurisdiction (Detail)
$ in Millions
 12 Months Ended
Dec. 31, 2016
USD ($)
Open Tax Years By Major Jurisdiction [Line Items]  
Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense $ 0.8
Unrecognized Tax Benefits, Income Tax Penalties Expense $ 0.7
KAZAKHSTAN  
Open Tax Years By Major Jurisdiction [Line Items]  
Open Tax Years by Major Tax Jurisdiction 2007-present
MEXICO  
Open Tax Years By Major Jurisdiction [Line Items]  
Open Tax Years by Major Tax Jurisdiction 2011-present
Russia [Member]  
Open Tax Years By Major Jurisdiction [Line Items]  
Open Tax Years by Major Tax Jurisdiction 2013-present
United States - Federal [Member]  
Open Tax Years By Major Jurisdiction [Line Items]  
Open Tax Years by Major Tax Jurisdiction 2009-present
United Kingdom [Member]  
Open Tax Years By Major Jurisdiction [Line Items]  
Open Tax Years by Major Tax Jurisdiction 2013-present