Shareholders' Equity (Details) - USD ($) $ in Millions	3 Months Ended	4 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Aug. 31, 2015
Stockholders' Equity Note [Abstract]
Number of shares of common stock authorized for buyback (in shares)			10,000,000
Remaining number of shares authorized to be repurchased (in shares)	7,512,574		10,299,198
Treasury stock, shares, acquired (in shares)	0	2,786,624
Treasury stock cumulative value acquired cost method		$ 112.0