CONSOLIDATED STATEMENT OF OPERATIONS - USD ($) shares in Thousands, $ in Thousands		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Income Statement [Abstract]
Net sales		$ 5,369,022	$ 5,363,046	$ 5,327,205	[1]
Cost of goods sold		4,609,161	4,526,551	4,524,676	[1]
Gross profit		759,861	836,495	802,529	[1]
Operating expenses:
Warehousing, marketing and administrative expenses		629,825	675,913	595,673	[1]
Defined benefit plan settlement loss		12,510
Impairments of goodwill and intangible assets			129,338	9,034	[1]
Loss (gain) on disposition of business			1,461	(800)	[1]
Operating income		117,526	29,783	198,622	[1]
Interest expense		24,143	20,580	16,234	[1]
Interest income		(1,272)	(996)	(500)	[1]
Income before income taxes		94,655	10,199	182,888	[1]
Income tax expense		30,803	54,541	70,773	[1]
Net income (loss)	[1]	$ 63,852	$ (44,342)	$ 112,115
Net income (loss) per share - basic:
Net income (loss) per share - basic		$ 1.75	$ (1.18)	$ 2.90	[1]
Average number of common shares outstanding - basic		36,580	37,457	38,705	[1]
Net income (loss) per share - diluted:
Net income (loss) per share - diluted		$ 1.73	$ (1.18)	$ 2.87	[1]
Average number of common shares outstanding - diluted		36,918	37,457	39,130	[1]
Dividends declared per share		$ 0.56	$ 0.56	$ 0.56	[1]

[1] Revised in 2015 for the impact of the changes in accounting principle related to inventory accounting.