Stock-Based Compensation (Narrative) (Details) (USD $) In Millions, except Share data, unless otherwise specified	9 Months Ended	3 Months Ended		9 Months Ended	1 Months Ended	3 Months Ended		9 Months Ended	1 Months Ended		1 Months Ended
	Sep. 30, 2014	Sep. 30, 2014 Restricted stock units [Member]	Mar. 31, 2014 Restricted stock units [Member]	Sep. 30, 2014 Restricted stock units [Member]	Mar. 31, 2014 Restricted stock units [Member] Awarded in 2014, 2013 and 2012 [Member]	Sep. 30, 2014 Stock Options [Member]	Mar. 31, 2014 Stock Options [Member]	Sep. 30, 2014 Stock Options [Member]	Mar. 31, 2014 Stock Options [Member] Awarded in 2014, 2013 and 2012 [Member]	Sep. 30, 2014 Plan [Member]	Mar. 31, 2014 Plan [Member] Stock Options [Member]
Share-Based Compensation [Line Items]
Number of shares authorized for grant										6,900,000
Number of shares available for future grant (in shares)										74,329
Number of shares of common stock exchanged for each award	1
Aggregate number of shares approved		5,508,333		5,508,333		2,785,465		2,785,465
Granted (in shares)								714,000			250,000
Number of restricted stock units for which performance targets are established (in shares)					866,500
Compensation expense		$ 3.2		$ 10.2		$ 1.3		$ 4.1
Unrecognized compensation cost related to the unvested awards		15.7		15.7		9.2		9.2
Weighted average period over which unrecognized compensation cost is expected to be recognized				2 years 9 months 18 days				2 years 10 months 24 days
Granted, weighted average grant date fair value (in dollars per share)			$ 27.33	$ 27.39
Forfeited (in shares)				(20,000)
Number of stock option awards subject to performance targets (in shares)									714,000
Weighted average grant date fair value							$ 17.69	$ 17.69
Term of stock options								10 years
Number of unvested stock awards that will vest subject to the satisfaction of service-based requirements and the achievement of performance metrics (in shares)				65,000
Number of unvested stock awards that will vest subject to the satisfaction of service-based requirements (in shares)				1,302,500
Number of vested and exercisable stock options (in shares)						1,210,000		1,210,000
Vested and exercisable stock options, weighted average exercise price (in dollars per share)						$ 20.35		$ 20.35
Number of unvested stock option awards that will vest subject to the satisfaction of service-based requirements (in shares)						475,000		475,000
Number of unvested stock option awards that will vest subject to the satisfaction of service-based requirements and the achievement of performance metrics (in shares)						1,850,000		1,850,000
Outstanding shares						1,989,000		1,989,000
Intrinsic value of outstanding stock options						$ 13.9		$ 13.9
Weighted average remaining contractual term of outstanding stock options								6 years 1 month 6 days