Stock-Based Compensation, Stock Options (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Compensation expense [Abstract]
Stock-based compensation cost	$ 6.6	$ 7.9	$ 9.5
Stock Options [Member]
Compensation expense [Abstract]
Stock-based compensation cost	1.3	1.2	1.2
Fair value of awards vesting	1.2	$ 1.2	$ 1.2
Unrecognized compensation costs	$ 2.4
Weighted average period recognized	2 years 6 months
Assumptions for stock awards granted [Abstract]
Fair value of options (in dollars per share)	$ 5.56	$ 7.81	$ 7.30
Expected life of awards in years	6 years 3 months 18 days	6 years 3 months 18 days	6 years 4 months 24 days
Risk-free interest rate	2.20%	2.80%	1.90%
Expected volatility of the Company's stock	39.20%	39.70%	44.30%
Expected dividend yield on the Company's stock	0.00%	0.00%	0.00%
Award vesting period	4 years
Stock options activity [Rollforward]
Outstanding, beginning (in shares)	1.2
Granted (in shares)	0.3
Exercised (in shares)	0.0
Forfeited or expired (in shares)	(0.1)
Outstanding, ending (in shares)	1.4	1.2
Exercisable, ending (in shares)	0.9
Weighted average exercise price [Rollforward]
Outstanding, beginning (in dollars per share)	$ 12.24
Granted (in dollars per share)	13.26
Exercised (in dollars per share)	7.13
Forfeited or expired (in dollars per share)	12.68
Outstanding, ending (in dollars per share)	12.49	$ 12.24
Exercisable, ending (in dollars per share)	$ 11.28
Summary of stock option activity [Abstract]
Options, Outstanding, Weighted average remaining contractual term	5 years 7 months 6 days
Options, Outstanding, Aggregate intrinsic value	$ 0.0
Options, Exercisable, Weighted average remaining contractual term	3 years 10 months 24 days
Options, Exercisable, Aggregate intrinsic value	$ 0.0
Additional information related to stock options exercised [Abstract]
Intrinsic value of stock options exercised	0.1	$ 0.7	$ 4.9
Proceeds from stock options exercised	$ 0.1	$ 1.1	$ 4.3
Stock Options [Member] \| Maximum [Member]
Assumptions for stock awards granted [Abstract]
Stock option term	10 years
Stock Options [Member] \| Tranche One [Member]
Assumptions for stock awards granted [Abstract]
Annual vesting percentage	25.00%
Stock Options [Member] \| Tranche Two [Member]
Assumptions for stock awards granted [Abstract]
Annual vesting percentage	25.00%
Stock Options [Member] \| Tranche Three [Member]
Assumptions for stock awards granted [Abstract]
Annual vesting percentage	25.00%
Stock Options [Member] \| Tranche Four [Member]
Assumptions for stock awards granted [Abstract]
Annual vesting percentage	25.00%

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Amount of cash inflow from exercise of option under share-based payment arrangement.

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The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term.

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The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period.

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The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.

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