Earnings per Common Share - Computation of Basic and Diluted Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Mar. 31, 2016	Mar. 31, 2015
Earnings Per Share, Basic [Abstract]
Net income	$ 4,357	$ (2,959)	$ 19,729	$ 6,241
Weighted average shares outstanding - basic (shares)	26,758	26,711	26,651	26,593
Basic EPS (US$ per share)	$ 0.16	$ (0.11)	$ 0.74	$ 0.23
Earnings Per Share, Diluted [Abstract]
Dilutive stock options	57	0	73	117
Dilutive nonvested deferred shares	239	0	467	465
Diluted weighted average shares (shares)	27,054	26,711	27,191	27,175
Diluted EPS (US$ per share)	$ 0.16	$ (0.11)	$ 0.73	$ 0.23