Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Income Statement [Abstract]
Revenues	$ 269,910	$ 341,781
Cost of revenues	241,019	309,503
Gross profit	28,891	32,278
Selling, general and administrative expenses	21,570	17,977
Operating income	7,321	14,301
Other income (expense):
Interest expense	(618)	(243)
Interest income	39	12
Other	149	7
Income before income tax expense	6,891	14,077
Provision for federal, state and foreign income taxes	3,067	4,735
Net income	$ 3,824	$ 9,342
Basic earnings (loss) per common share (US$ per share)	$ 0.14	$ 0.35
Diluted earnings (loss) per common share (US$ per share)	$ 0.14	$ 0.35
Weighted average common shares outstanding:
Basic (shares)	26,655	26,387
Diluted (shares)	26,762	26,796