Income Taxes - Tax effects of significant temporary differences of deferred tax assets and liabilities (Details 3) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2011
Deferred tax assets:
Employee related accruals	$ 12,417	$ 10,709
Environmental remediation	2,306	2,348
Net operating loss carry forwards-domestic	19,183	18,790
Net operating loss carry forwards-foreign	8,729	9,860
Other	9,540	8,413
Deferred tax assets, gross	52,175	50,120
Valuation allowance	(32,892)	(27,753)	(36,763)	(30,618)
Deferred tax assets, net of valuation allowance	19,283	22,367
Deferred tax liabilities:
Property, plant and equipment and intangible assets	(13,428)	(14,645)
Unrealized foreign exchange gains	(4,680)	(4,827)
Other	(131)	(573)
Deferred tax liabilities, net	(18,239)	(20,045)
Net deferred tax asset (liability)	$ 1,044	$ 2,322