Details of Movement in Restructuring Provisions Recognized (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	6 Months Ended	12 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012	Dec. 31, 2012	Mar. 31, 2013 1st Quarter 2013 Restructuring Plan	Jun. 30, 2013 1st Quarter 2013 Restructuring Plan	Jun. 30, 2013 2nd Quarter 2013 Restructuring Plan	Jun. 30, 2013 2nd Quarter 2013 Restructuring Plan	Jun. 30, 2013 Restructuring - Fiscal 2012 Plan	Dec. 31, 2012 Restructuring - Fiscal 2012 Plan	Jun. 30, 2013 Workforce Reduction	Jun. 30, 2013 Workforce Reduction 1st Quarter 2013 Restructuring Plan	Jun. 30, 2013 Workforce Reduction 2nd Quarter 2013 Restructuring Plan	Jun. 30, 2013 Workforce Reduction Restructuring - Fiscal 2012 Plan	Dec. 31, 2012 Workforce Reduction Restructuring - Fiscal 2012 Plan	Jun. 30, 2013 Office Consolidations	Jun. 30, 2013 Office Consolidations 1st Quarter 2013 Restructuring Plan	Jun. 30, 2013 Office Consolidations 2nd Quarter 2013 Restructuring Plan	Jun. 30, 2013 Office Consolidations Restructuring - Fiscal 2012 Plan	Dec. 31, 2012 Office Consolidations Restructuring - Fiscal 2012 Plan
Restructuring Cost and Reserve [Line Items]
Initial provision recognized	$ 4,621	$ 4,525	$ 9,033	$ 4,525	$ 4,500	$ 4,400	$ 4,412	$ 4,600	$ 4,621		$ 4,644	$ 8,131	$ 3,903	$ 4,228		$ 3,394	$ 902	$ 509	$ 393		$ 1,250
Cash payments			(4,369)							(623)	(3,854)	(4,280)			(197)	(3,030)	(89)			(426)	(824)
Foreign exchange movement			(3)								(4)	(3)				(4)
Provision balance at end of period	$ 4,661		$ 4,661							$ 163	$ 786	$ 3,848			$ 163	$ 360	$ 813				$ 426

Amount of cash payments made as the result of exit or disposal activities. Excludes payments associated with a discontinued operation or an asset retirement obligation.

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Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.

+ References

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Carrying amount (including both current and noncurrent portions of the accrual) as of the balance sheet date pertaining to a specified type of cost associated with exit from or disposal of business activities or restructuring pursuant to a duly authorized plan.

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Amount of foreign currency translation adjustment increasing or decreasing the accrual for a specified type of restructuring cost.

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