Fair Value Measurements (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Jun. 30, 2015
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Trust assets	$ 1,002	$ 977
Money Market	34	27
U.S. Equity Securities	421	395
Foreign Equity Funds	169	185
U.S. Fixed Income Securities	216	177
Foreign Fixed Income Funds	18	57
Absolute Return Strategy Mutual Funds	144	136
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
4.26% Series A Notes	50,797	52,935
Reported Value Measurement [Member]
Fair Value, Balance Sheet Grouping, Financial Statement Captions [Line Items]
4.26% Series A Notes	$ 52,000	$ 53,500