Condensed Consolidated Statements of Income - USD ($) shares in Thousands, $ in Thousands	3 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Income Statement [Abstract]
Revenues	$ 318,511	$ 269,910
Cost of revenues	295,090	241,019
Gross profit	23,421	28,891
Selling, general and administrative expenses	21,201	21,570
Operating income	2,220	7,321
Other income (expense):
Interest expense	(292)	(618)
Interest income	282	39
Other	546	149
Income before income tax expense	2,756	6,891
Provision for federal, state and foreign income taxes	451	3,067
Net income	$ 2,305	$ 3,824
Basic earnings per common share (US$ per share)	$ 0.09	$ 0.14
Diluted earnings per common share (US$ per share)	$ 0.08	$ 0.14
Weighted average common shares outstanding:
Basic (shares)	26,921	26,655
Diluted (shares)	27,589	26,762