Share repurchase program (Details) (USD $)	3 Months Ended	9 Months Ended
	Mar. 31, 2014	Mar. 31, 2014
Equity, Class of Treasury Stock [Line Items]
Authorization to repurchase common shares, percentage of shares of common stock outstanding at the end of the prior fiscal year	5.00%
Share repurchased (in shares)	415,076	1,339,061
Treasury Stock Acquired, Average Cost Per Share	$ 120.46	$ 112.02
Maximum [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Number of Shares Authorized to be Repurchased (in shares)	7,500,000	7,500,000