Quarterly Results of Operations (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended																12 Months Ended
	Dec. 31, 2018		Sep. 30, 2018		Jun. 30, 2018		Mar. 31, 2018		Dec. 31, 2017		Sep. 30, 2017		Jun. 30, 2017		Mar. 31, 2017		Dec. 31, 2018		Dec. 31, 2017		Dec. 31, 2016
Net Sales	$ 1,070,493		$ 1,306,999		$ 1,059,103		$ 1,012,280		$ 995,703		$ 1,266,930		$ 1,021,814		$ 805,407		$ 4,448,875		$ 4,089,854		$ 3,612,914
Gross profit	152,372		204,107		173,250		160,034		152,233	[1]	205,641	[1]	158,694	[1]	117,980	[1]	689,763		634,548		511,849
Net income	$ 38,191	[2]	$ 84,739	[2]	$ 55,343	[2]	$ 45,721	[2]	$ 146,119	[3]	$ 72,382	[3]	$ 27,926	[3]	$ 23,232	[3]	$ 223,994		$ 269,659		$ 153,351
Basic net income per share (in dollars per share)	$ 0.35	[2],[4]	$ 0.77	[2],[4]	$ 0.50	[2],[4]	$ 0.41	[2],[4]	$ 1.32	[3],[4]	$ 0.66	[3],[4]	$ 0.25	[3],[4]	$ 0.21	[3],[4]	$ 2.03	[5]	$ 2.44	[5]	$ 1.28	[5]
Diluted net income per share (in dollars per share)	0.34	[2],[4]	0.76	[2],[4]	0.50	[2],[4]	0.41	[2],[4]	1.31	[3],[4]	0.65	[3],[4]	0.25	[3],[4]	0.21	[3],[4]	$ 2.01	[5]	$ 2.42	[5]	$ 1.27	[5]
Dividends per share (in dollars per share)	$ 0.10		$ 0.10		$ 0.10		$ 0.10		$ 0.09		$ 0.09		$ 0.09		$ 0.09
Rationalization charges	$ 4,800	[2]	$ 300	[2]	$ 500	[2]	$ 700	[2]	$ 1,300	[2]	$ 600	[2]	$ 3,000	[2]	$ 900	[2]	$ 6,253		$ 5,826		$ 19,061
Loss on early extinguishment of debt					$ 2,500								4,400		2,700		2,493		7,052		0
Income tax benefit from impact of 2017 Tax Act									110,900
Business Combination, Acquisition Related Costs									900		800		9,800		13,200
Corporate Segment [Member]
Net Sales																	$ 0		0		0
Rationalization charges																			0		0
Business Combination, Acquisition Related Costs																			$ 24,700		$ 1,400
Accounting Standards Update 2017-07 [Member]
Gross profit									$ (6,600)		$ (6,900)		$ (6,500)		$ (6,600)

[1] In 2018, we retrospectively adopted new accounting guidance which amended the presentation of net periodic pension and other postretirement benefit costs. As a result, gross profit was decreased by $6.6 million, $6.5 million, $6.9 million and $6.6 million in the first, second, third and fourth quarters of 2017, respectively. See Note 1 for further information.

[2] The first, second, third and fourth quarters of 2018 include rationalization charges of $0.7 million, $0.5 million, $0.3 million and $4.8 million, respectively. The second quarter of 2018 includes a loss on early extinguishment of debt of $2.5 million.

[3] The first, second, third and fourth quarters of 2017 include rationalization charges of $0.9 million, $3.0 million, $0.6 million and $1.3 million, respectively. The first, second, third and fourth quarters of 2017 includes costs attributed to announced acquisitions of $13.2 million, $9.8 million, $0.8 million and $0.9 million, respectively. The first and second quarters of 2017 include a loss on early extinguishment of debt of $2.7 million and $4.4 million, respectively. The fourth quarter of 2017 includes the benefit from effective tax rate adjustments totaling $110.9 million primarily related to the remeasurement of net deferred tax liabilities to reflect the lower future cash tax obligations as a result of the reduction in the federal corporate tax rate under the 2017 Tax Act.

[4] Net income per share data is computed independently for each of the periods presented. Accordingly, the sum of the quarterly earnings per share amounts may not equal the total for the year.

[5] Per share amounts for 2016 have been retroactively adjusted for the two-for-one stock split discussed in Note 1.