Stock-Based Compensation, Phantom Stock Option Plan and Long-term Incentive Plan (Details) - 2011 Phantom Stock Option and Long-term Incentive Plan [Member] - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016	Jun. 30, 2017
Stock option related information [Abstract]
Total liability for long-term incentive plan	$ 1,700		$ 1,700		$ 2,000
Phantom Stock Option [Member]
Stock option activity, shares [Roll Forward]
Outstanding at beginning of year (in shares)			1,522,720	1,352,554
Options granted (in shares)			594,200	578,200
Options forfeited (in shares)			(27,000)	0
Options paid in cash (in shares)			(455,760)	(408,034)
Outstanding at period end (in shares)	1,634,160	1,522,720	1,634,160	1,522,720
Stock option related information [Abstract]
Cash paid out on options vested	$ 1,184	$ 845	$ 1,187	$ 845
Compensation costs recognized	$ 460	$ 347	$ 820	$ 588