Condensed Consolidated Income Statements (Unaudited) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013	Mar. 31, 2012
Income Statement [Abstract]
Net sales	$ 682,965	$ 707,883	$ 2,164,286	$ 2,260,827
Cost of goods sold	614,133	638,615	1,947,063	2,032,630
Gross profit	68,832	69,268	217,223	228,197
Selling, general and administrative expenses	47,937	46,711	144,392	141,753
Change in fair value of contingent consideration	100	1,072	1,396	1,244
Operating income	20,795	21,485	71,435	85,200
Interest expense	102	254	356	1,490
Interest income	(483)	(780)	(1,648)	(2,233)
Other (income) expense, net	(4)	206	34	3,363
Income before income taxes	21,180	21,805	72,693	82,580
Provision for income taxes	7,202	7,049	24,716	28,077
Net income	$ 13,978	$ 14,756	$ 47,977	$ 54,503
Per share data:
Weighted-average shares outstanding, basic (in shares)	27,847	27,489	27,725	27,290
Net income per common share, basic (in dollars per share)	$ 0.50	$ 0.54	$ 1.73	$ 2.00
Weighted-average shares outstanding, diluted (in shares)	28,024	27,926	27,960	27,709
Net income per common share, diluted (in dollars per share)	$ 0.50	$ 0.53	$ 1.72	$ 1.97