Commitments and Contingent Liabilities - Additional Information (Detail) In Thousands, unless otherwise specified	12 Months Ended				12 Months Ended
	Dec. 31, 2013 USD ($) Agreement	Dec. 31, 2013 GBP (£)	Dec. 31, 2010 USD ($)	Dec. 31, 2010 GBP (£)	Dec. 31, 2013 Collective Bargaining Agreement One [Member]	Dec. 31, 2013 Collective Bargaining Agreement Two [Member]
Commitments And Contingent Liabilities [Line Items]
Outstanding standby and commercial letters of credit	$ 17,906
Government grants awarded			1,325	850
Government grants received	1,083	680
Recorded liability	$ 0
Percentage on employees covered by collective bargaining agreements	55.00%	55.00%
Number of bargaining agreements	6	6
Number of expired agreements	1	1
Percentage of covered employees					20.00%	62.00%
Bargaining agreement expiration year	2012	2012
Bargaining agreement beginning expiration year	2014-05	2014-05
Bargaining agreement ending expiration year	2017-10	2017-10