Unaudited Quarterly Results of Operations (Detail) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Quarterly Financial Information Disclosure [Abstract]
Net sales	$ 523,899	$ 533,179	$ 546,693	$ 543,996	$ 520,620	$ 490,617	$ 518,445	$ 494,448	$ 2,147,767		$ 2,024,130		$ 1,954,258
Gross profit	229,117	234,646	241,132	244,420	227,009	211,509	222,849	211,997	949,315		873,364		803,700
Operating income	94,454	110,847	112,088	113,835	103,873	97,369	99,559	94,712	431,224	[1]	395,513	[1]	128,218	[1]
Net income	$ 61,620	$ 71,441	$ 71,777	$ 74,548	$ 67,555	$ 63,799	$ 62,561	$ 61,300	$ 279,386		$ 255,215		$ 37,630
Basic EPS	$ 0.78	$ 0.89	$ 0.89	$ 0.92	$ 0.83	$ 0.78	$ 0.76	$ 0.74	$ 3.48		$ 3.11		$ 0.45
Diluted EPS	$ 0.77	$ 0.88	$ 0.88	$ 0.91	$ 0.82	$ 0.78	$ 0.76	$ 0.74	$ 3.45		$ 3.09		$ 0.45
Basic weighted average shares outstanding	78,669	79,558	80,106	80,527	80,782	81,259	81,829	82,197	79,715		81,517		82,689
Diluted weighted average shares outstanding	79,632	80,561	81,149	81,575	81,854	82,218	82,734	83,152	80,728		82,489		83,641

[1] Segment operating income (loss) excludes net unallocated corporate operating expenses.