Basis of Presentation and Summary of Significant Accounting Policies - Schedule of Changes Impact to Financial Results (Details) - 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		Dec. 31, 2015
Net sales	$ 564,118	$ 510,580	$ 546,430	$ 542,832	$ 544,770	$ 543,275	$ 556,082	$ 522,760	$ 2,163,960	$ 2,166,887	$ 2,239,557
Gross profit	$ 84,795	$ 85,134	$ 90,417	$ 83,596	$ 79,628	$ 81,457	$ 85,145	$ 78,498	343,942	$ 324,728	$ 318,927
Gross profit margin										14.99%	14.24%
Operating profit									40,746	$ 10,628	$ 34,901
Income tax expense									9,257	667	11,158
Net income									$ 22,773	$ 2,595	$ 17,660
Net earnings per share: Basic										$ 0.21	$ 1.49	[1]
Net earnings per share: Diluted	$ 0.48	$ 0.47	$ 0.64	$ 0.23	$ (0.27)	$ (0.06)	$ 0.18	$ 0.31	$ 1.83	$ 0.20	$ 1.41
Accounts receivable, net	$ 463,487				$ 439,658				$ 463,487	$ 439,658	$ 368,596
Inventories	61,617				103,471				61,617	103,471	72,219
Total current assets	539,671				561,575				539,671	561,575	470,049
Total assets	720,950				740,252				720,950	740,252	630,804
Accounts payable	357,212				289,201				357,212	289,201	276,704
Total current liabilities	520,073				569,294				520,073	569,294	474,232
Deferred income tax liabilities	1,894				3,102				1,894	3,102	1,815
Total liabilities	568,057				612,626				568,057	612,626	501,837
Retained earnings	54,021				31,248				54,021	31,248	28,747
Total stockholders' equity	152,893				127,626				152,893	127,626	128,967		$ 109,944
Total liabilities and stockholders' equity	$ 720,950				$ 740,252				$ 720,950	740,252	630,804
As Reported[Member]
Net sales										2,193,436	2,250,587
Gross profit										$ 325,722	$ 318,801
Gross profit margin										14.85%	14.17%
Operating profit										$ 11,441	$ 34,791
Income tax expense										984	11,115
Net income										$ 3,091	$ 17,593
Net earnings per share: Basic										$ 0.25	$ 1.49
Net earnings per share: Diluted										$ 0.24	$ 1.40
Accounts receivable, net											$ 358,949
Inventories											80,872
Total current assets											469,055
Total assets											629,810
Accounts payable											276,524
Total current liabilities											474,052
Deferred income tax liabilities											1,498
Total liabilities											501,339
Retained earnings											28,251
Total stockholders' equity											128,471
Total liabilities and stockholders' equity											629,810
New Revenue Recognition Standard Adjustment [Member]
Net sales										$ (26,549)	(11,030)
Gross profit										$ (994)	$ 126
Gross profit margin										14.00%	8.00%
Operating profit										$ (813)	$ 110
Income tax expense										(317)	43
Net income										$ (496)	$ 67
Net earnings per share: Basic										$ (0.04)	$ 0.01
Net earnings per share: Diluted										$ (0.04)	$ 0.01
Accounts receivable, net											$ 9,647
Inventories											(8,653)
Total current assets											994
Total assets											994
Accounts payable											180
Total current liabilities											180
Deferred income tax liabilities											317
Total liabilities											498
Retained earnings											496
Total stockholders' equity											496
Total liabilities and stockholders' equity											$ 994

[1] Amount does not foot across due to rounding.