Condensed Consolidated Income Statements (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Mar. 31, 2014	Mar. 31, 2013	Mar. 31, 2014	Mar. 31, 2013
Income Statement [Abstract]
Net sales	$ 682,998	$ 682,965	$ 2,155,520	$ 2,164,286
Cost of goods sold	609,647	614,133	1,928,414	1,947,063
Gross profit	73,351	68,832	227,106	217,223
Selling, general and administrative expenses	46,705	47,937	143,541	144,392
Change in fair value of contingent consideration	981	100	2,218	1,396
Operating income	25,665	20,795	81,347	71,435
Interest expense	217	102	698	356
Interest income	(545)	(483)	(1,644)	(1,648)
Other (income) expense, net	13	(4)	65	34
Income before income taxes	25,980	21,180	82,228	72,693
Provision for income taxes	9,031	7,202	27,544	24,716
Net income	$ 16,949	$ 13,978	$ 54,684	$ 47,977
Per share data:
Weighted-average shares outstanding, basic (in shares)	28,502	27,847	28,275	27,725
Net income per common share, basic (in dollars per share)	$ 0.59	$ 0.50	$ 1.93	$ 1.73
Weighted-average shares outstanding, diluted (in shares)	28,730	28,024	28,548	27,960
Net income per common share, diluted (in dollars per share)	$ 0.59	$ 0.50	$ 1.92	$ 1.72