Quarterly Financial Data (Detail) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Quarterly Financial Data [Abstract]
Sales	$ 1,431,049	$ 1,478,726	$ 1,364,920	$ 1,153,782	$ 1,217,789	$ 1,185,067	$ 1,130,777	$ 982,996	$ 5,428,477	$ 4,516,629	$ 4,719,290
Gross profit	367,812	363,962	350,386	242,491	312,772	260,770	284,503	247,578	1,324,651	1,105,623	1,339,042
Net income	$ 31,474	$ 81,888	$ 62,041	$ (2,911)	$ 62,581	$ 32,312	$ 71,166	$ 46,889	$ 172,492	$ 212,948	$ 455,361
Diluted net income per share (in dollars per share)	$ 0.49	$ 1.28	$ 0.97	$ (0.05)	$ 0.97	$ 0.50	$ 1.09	$ 0.71	$ 2.69	$ 3.27	$ 6.75