Subsequent Events (Details) - Subsequent events - USD ($) $ in Millions	1 Months Ended
	Oct. 31, 2015	Oct. 27, 2015	Oct. 20, 2015
Subsequent Events
Treasury stock shares acquired	126,100
Treasury stock value acquired	$ 1.4
Commonwealth Bank | Interest rate swaps
Subsequent Events
Amortizing notional amount			$ 85.7
Fixed interest rate (as a percent)			1.43%
Citibank | Interest rate swaps
Subsequent Events
Amortizing notional amount		$ 128.6
Fixed interest rate (as a percent)		1.38%