Net Income Per Common Share (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Sep. 30, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2014
Earnings Per Share [Abstract]
Net income attributable to common stockholders—basic									$ 89,812	$ 651	$ 12,063
Net income attributable to nonvested restricted stockholders									106	1	69
Net income	$ 84,239	$ 1,192	$ 5,561	$ (1,074)	$ (2,187)	$ (2,572)	$ 2,896	$ 2,515	$ 89,918	$ 652	$ 12,132
Weighted average common shares outstanding - basic (in shares)									16,502,523	16,127,610	15,909,631
Shares issuable under stock options (in shares)									124,879	139,524	104,956
Weighted average common shares outstanding—diluted (in shares)									16,627,402	16,267,134	16,014,587
Net income (loss) per common share - basic (in US$ per share)	$ 5.09	$ 0.07	$ 0.34	$ (0.07)	$ (0.13)	$ (0.16)	$ 0.18	$ 0.16	$ 5.45	$ 0.04	$ 0.76
Net income (loss) per common share - diluted (in US$ per share)	$ 5.05	$ 0.07	$ 0.34	$ (0.07)	$ (0.13)	$ (0.16)	$ 0.18	$ 0.16	$ 5.41	$ 0.04	$ 0.76