Unaudited Quarterly Financial Data Unaudited Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Quarterly Financial Data [Abstract]
Net sales	$ 890,564	$ 964,249	$ 946,375	$ 825,405	$ 859,521	$ 990,264	$ 998,461	$ 834,202	$ 3,626,593	$ 3,682,448	$ 3,365,968
Gross profit	234,638	254,767	245,777	216,122	229,230	241,303	239,599	199,084	951,304	909,216	795,515
Net income	$ 20,199	$ 33,597	$ 35,699	$ 20,350	$ 28,116	$ 35,858	$ 40,405	$ 15,359	$ 109,845	$ 119,738	$ 57,425
Basic income (loss) per share
Net income (loss) per share (in dollars per share)	$ 0.30	$ 0.50	$ 0.54	$ 0.30	$ 0.42	$ 0.53	$ 0.60	$ 0.23	$ 1.65	$ 1.78	$ 0.86
Diluted income (loss) per share
Net income (loss) per share (in dollars per share)	$ 0.30	$ 0.50	$ 0.53	$ 0.30	$ 0.41	$ 0.53	$ 0.60	$ 0.23	$ 1.63	$ 1.77	$ 0.85