Stock-Based Compensation, Phantom Stock Option Plan and Long-term Incentive Plan (Details) - USD ($) $ in Thousands	12 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Stock option activity, shares [Roll Forward]
Options granted (in shares)	0	0
Phantom Stock Option [Member]
Stock option activity, shares [Roll Forward]
Outstanding at beginning of year (in shares)	64,770	95,670
Outstanding at year end (in shares)	37,770	64,770
2011 Phantom Stock Option and Long-term Incentive Plan [Member]
Share-based compensation arrangement by share-based payment award [Line Items]
Number of shares authorized under the plan (in shares)	3,600,000	3,600,000
Number of options granted to date (in shares)	2,972,982	2,394,782
Stock option activity, shares [Roll Forward]
Outstanding at beginning of year (in shares)	1,352,554	1,257,508
Options granted (in shares)	578,200	493,760
Options forfeited (in shares)	0	(2,000)
Options paid in cash upon vesting (in shares)	(408,034)	(396,714)
Outstanding at year end (in shares)	1,522,720	1,352,554
Stock option related information [Abstract]
Cash paid out on options vested	$ 845	$ 711
Compensation expense recognized	1,448	1,013
Total liability for long-term incentive plan	$ 2,000	$ 1,400
2011 Phantom Stock Option and Long-term Incentive Plan [Member] | Minimum [Member]
Share-based compensation arrangement by share-based payment award [Line Items]
Strike price of phantom stock options as percent of book value	100.00%