Consolidated Statements Of Income - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Income Statement [Abstract]
Sales	$ 5,428,477	$ 4,516,629	$ 4,719,290
Cost of sales	4,103,826	3,411,006	3,380,248
Gross profit	1,324,651	1,105,623	1,339,042
Operating expenses:
Selling and marketing	471,805	342,235	316,669
Research and development	238,299	185,126	166,460
General and administrative	331,196	306,442	209,077
Total operating expenses	1,041,300	833,803	692,206
Income from financial services	76,306	78,458	69,303
Operating income	359,657	350,278	716,139
Non-operating expense:
Interest expense	32,155	16,319	11,456
Equity in loss of other affiliates	6,760	6,873	6,802
Other expense, net	1,951	13,835	12,144
Income before income taxes	318,791	313,251	685,737
Provision for income taxes	146,299	100,303	230,376
Net income	$ 172,492	$ 212,948	$ 455,361
Net income per share:
Basic (in dollars per share)	$ 2.74	$ 3.31	$ 6.90
Diluted (in dollars per share)	$ 2.69	$ 3.27	$ 6.75
Weighted average shares outstanding:
Basic (in shares)	62,916	64,296	66,020
Diluted (in shares)	64,180	65,158	67,484