Stock Incentive Plans - Long term incentive plans (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Disclosure of Compensation Related Costs, Share-based Payments [Abstract]
Performance period (in years)	3 years
LTIP
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
LTIP three-year plan	. 17, 2015	. 16, 2014	. 15, 2013
Number of shares issued	308,278	227,707	175,291
Share value on date of issuance (in USD per share)	$ 176.39	$ 157.07	$ 113.91
Total value	$ 54,377	$ 35,766	$ 19,967