Share-Based Payment Arrangements - Schedule of Option Activity Under Stock Option Plans (Detail) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended
	Mar. 31, 2013
Disclosure Of Compensation Related Costs Sharebased Payments [Abstract]
Number of Shares, Outstanding at Beginning Balance	1,555,296
Number of Shares, Exercised	(5,774)
Number of Shares, Forfeited or expired	(16,084)
Number of Shares, Outstanding at Ending Balance	1,533,438
Number of Shares, Exercisable at Ending Balance	1,047,850
Weighted- Average Exercise Price, Outstanding at Beginning Balance	$ 38.57
Weighted- Average Exercise Price, Exercised	$ 22.74
Weighted- Average Exercise Price, Forfeited or expired	$ 35.49
Weighted- Average Exercise Price, Outstanding at Ending Balance	$ 38.67
Weighted- Average Exercise Price, Exercisable at Ending Balance	$ 41.81
Weighted-Average Remaining Contractual Term, Outstanding at Ending Balance (in years)	5 years
Weighted-Average Remaining Contractual Term, Exercisable at Ending Balance (in years)	3 years 7 months 6 days
Aggregate Intrinsic Value, Outstanding at Ending Balance	$ 615
Aggregate Intrinsic Value, Exercisable at Ending Balance	$ 292