Debt - Additional Information (Detail) In Thousands, unless otherwise specified	6 Months Ended			6 Months Ended											1 Months Ended		6 Months Ended
	Jun. 30, 2013 USD ($)	Jun. 30, 2013 EUR (€)	Feb. 28, 2013 Europe Term Note USD ($)	Jun. 30, 2013 W.E.T. Bank of America credit facility	Jun. 30, 2013 W.E.T. Bank of America credit facility Minimum	Jun. 30, 2013 Eurocurrency Rate Loans	Jun. 30, 2013 Eurocurrency Rate Loans Minimum	Jun. 30, 2013 Eurocurrency Rate Loans Maximum	Jun. 30, 2013 Federal Funds Rate Minimum	Jun. 30, 2013 Federal Funds Rate Maximum	Jun. 30, 2013 US Bank of America credit facility Maximum	Jun. 30, 2013 Base Rate Loans	Jun. 30, 2013 Bank of China USD ($)	Jun. 30, 2013 Bank of China CNY	Jun. 30, 2013 DEG Loan EUR (€)	May 31, 2013 DEG Loan	Jun. 30, 2013 DEG Loan USD ($)	Jun. 30, 2013 DEG Loan EUR (€)	May 31, 2013 DEG Loan Euribor Rate	Jun. 30, 2013 DEG Loan Euro Swap Rate
Debt Disclosure [Line Items]
Principal amortization of credit facility percentage year one	10.00%	10.00%
Principal amortization of credit facility percentage year two	12.50%	12.50%
Principal amortization of credit facility percentage year three	15.00%	15.00%
Principal amortization of credit facility percentage year four	17.50%	17.50%
Principal amortization of credit facility percentage year five	10.00%	10.00%
Quarterly principal payments				20.00%
Credit facility due date	Mar. 30, 2016	Mar. 30, 2016
Debt instrument, description	The Company has the option to elect interest rates based on either a Eurocurrency (LIBOR or EUIBOR) rate (“Eurocurrency Rate Loans”) (0.20% – 0.40% at June 30, 2013) or a base rate (“Base Rate Loans”) plus a margin (“Applicable Rate”), which varies based on the Consolidated Leverage Ratio of the Company, as defined by the US and W.E.T. Bank of America credit agreements.	The Company has the option to elect interest rates based on either a Eurocurrency (LIBOR or EUIBOR) rate (“Eurocurrency Rate Loans”) (0.20% – 0.40% at June 30, 2013) or a base rate (“Base Rate Loans”) plus a margin (“Applicable Rate”), which varies based on the Consolidated Leverage Ratio of the Company, as defined by the US and W.E.T. Bank of America credit agreements.
Interest rate					1.00%	2.25%	0.20%	0.40%	0.07%	0.50%	3.25%	1.25%	6.90%	6.90%	1.05%	0.231%	3.23%	3.23%
Debt instrument face amount													$ 3,159	20,000
Fixed interest rate													6.90%	6.90%
Amount of draw on europe term note			40,441
Line of credit available amount	29,550	20,000													2,000			2,000
Outstanding letter of credit	450
Initial amount drawn from German Investment Corporation																	2,601	2,000
Additional amount to be drawn	$ 29,550	€ 20,000													€ 2,000			€ 2,000
Spread variable interest rate																			3.00%	3.00%
Spread variable interest rate																			3.00%	3.00%