Acquisitions - Pro forma information (Details) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Business Combinations [Abstract]
Business Combination, Pro Forma Information, Revenue of Acquiree since Acquisition Date, Actual	$ 21,500,000
Business Combination, Pro Forma Information, Net Income of Acquiree Since Acquisition Date, Actual	200,000
Business Combination, Pro Forma Information, Transactional Costs of Acquiree since Acquisition Date, Actual	900,000
Net sales	820,649,000	807,244,000
Cost of sales	596,178,000	593,870,000
Gross profit	224,471,000	213,374,000
Selling, general & administrative expenses	168,794,000	169,433,000
Operating income	55,677,000	43,941,000
Interest expense, net	7,333,000	7,931,000
Income from continuing operations	48,344,000	36,010,000
Income taxes	17,784,000	9,508,000
Net income	$ 30,560,000.00	$ 26,502,000.00
Business Acquisition, Pro Forma Earnings Per Share, Basic	$ 0.91	$ 0.77
Business Acquisition, Pro Forma Earnings Per Share, Diluted	$ 0.90	$ 0.76