Schedule of Compensation Cost for Stock Options and Unvested Shares (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Total expense before income taxes	$ 20,717	$ 16,993	$ 13,102
Stock Option
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Total expense before income taxes	6,826	6,268	6,292
Income tax benefit	(2,194)	(2,016)	(1,988)
Total expense after income taxes	4,632	4,252	4,304
Stock Option | Cost Of Goods Sold
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Total expense before income taxes	581	479	650
Stock Option | Selling, general and administrative expenses
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Total expense before income taxes	6,245	5,789	5,642
Unvested Shares
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Total expense before income taxes	10,670	9,851	6,810
Income tax benefit	(2,233)	(2,296)	(1,682)
Total expense after income taxes	8,437	7,555	5,128
Unvested Shares | Cost Of Goods Sold
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Total expense before income taxes	1,753	1,380	991
Unvested Shares | Selling, general and administrative expenses
Compensation Related Costs Share Based Payments Disclosure [Line Items]
Total expense before income taxes	$ 8,917	$ 8,471	$ 5,819