Stockholders' Equity (Common Stock Shares Activity) (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Jun. 30, 2017		Mar. 31, 2017
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Treasury stock, shares, beginning of period	7,013,777		5,398,596
Treasury stock, shares, end of period	8,124,611		7,013,777
Repurchase of common stock	1,110,834	[1]	1,615,181	[2]
Common stock, Class A
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Common stock, shares issued, beginning of period	155,901,485		153,391,058
Issuance of common stock	465,989		578,932
Stock options exercised	433,242		1,931,495
Common stock, shares issued, end of period	156,800,716		155,901,485
Repurchase of common stock	1,000,000		1,300,000
Repurchase of common stock, value, cost method	$ 33.9		$ 46.4

[1] (2)During the first quarter of fiscal 2018, the Company purchased 1.0 million shares of the Company’s Class A Common Stock in a series of open market transactions for $33.9 million. Additionally, the Company repurchased shares during the first quarter of fiscal 2018 to cover the minimum statutory withholding taxes on restricted stock awards and restricted stock units that vested on June 30, 2017.

[2] During fiscal 2017, the Company purchased 1.3 million shares of the Company’s Class A Common Stock in a series of open market transactions for $46.4 million. Additionally, the Company repurchased shares during fiscal 2017 to cover the minimum statutory withholding taxes on restricted stock awards and restricted stock units that vested on March 31, 2017. The Company also repurchased shares to cover the minimum statutory withholding taxes on restricted stock for departing officers