Consolidated Statements of Operations - USD ($) shares in Thousands, $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Net sales	$ 2,163,960	$ 2,166,887	$ 2,239,557
Cost of goods sold	1,820,018	1,842,159	1,920,630
Gross profit	343,942	324,728	318,927
Selling, general and administrative expenses	303,196	314,100	284,026
Operating profit	40,746	10,628	34,901
Interest expense, net	9,486	7,894	6,083
Equity income from unconsolidated affiliate	770	528
Income before income taxes	32,030	3,262	28,818
Income tax expense	9,257	667	11,158
Net income	$ 22,773	$ 2,595	$ 17,660
Basic and Diluted Earnings Per Common Share
Basic	$ 1.90	$ 0.21	$ 1.49
Diluted	$ 1.83	$ 0.20	$ 1.41
Weighted average number of common shares outstanding
Basic	11,993	12,269	11,847
Diluted	12,437	13,094	12,528