W.E.T. Acquisition - Additional Information (Detail) In Thousands, except Share data, unless otherwise specified	1 Months Ended		12 Months Ended		1 Months Ended
	May 16, 2012 USD ($)	May 16, 2011 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2012	May 16, 2012 W.E.T. [Member] EUR (€)	Aug. 31, 2011 W.E.T. [Member] USD ($)	Aug. 31, 2011 W.E.T. [Member] EUR (€)	May 26, 2011 W.E.T. [Member] USD ($)	May 26, 2011 W.E.T. [Member] EUR (€)	May 16, 2011 W.E.T. [Member] USD ($)	May 16, 2011 W.E.T. [Member] EUR (€)
Acquisitions [Line Items]
Business acquisition shares of voting interests acquired	110,325			2,660				2,903	2,903	2,316,175	2,316,175
Business acquisition percentage of voting interests acquired				76.00%				76.28%	76.28%	76.19%	76.19%
Tender offer price per share											€ 40
Total business acquisition consideration								$ 130,889	€ 92,763
Business acquisition debt assumed								51,570	36,322
Business acquisition cash acquired		17,457						17,457	12,372
Business acquisition treasury shares issued					143,683	16,305	16,305
Treasury stock price per share					€ 44.95	$ 67.97	€ 50.00
Treasury shares acquired value	6,400		3,380
Account Receivable, Gross										59,438
Account Receivable, expected uncollectible										$ 1,968