Share-Based Compensation (Stock Option Activity) (Details) - USD ($) $ / shares in Units, $ in Thousands	6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019
Shares
Outstanding, beginning of period (in shares)	1,020,200	944,600
Granted (in shares)	249,900	302,700
Exercised (in shares)	(62,800)	(18,400)
Forfeited or expired (in shares)	0	(124,700)
Outstanding, end of period (in shares)	1,207,300	1,104,200
Exercisable, end of period (in shares)	699,100	610,200
Weighted Average Exercise Price
Outstanding, beginning of period, weighted-average exercise price (in USD per share)	$ 35.90	$ 38.45
Granted, weighted-average exercise price (in USD per share)	39.98	30.53
Exercised, weighted-average exercise price (in USD per share)	20.46	29.57
Forfeited or expired, weighted-average exercise price (in USD per share)	0	43.08
Outstanding, end of period, weighted-average exercise price (in USD per share)	37.55	35.90
Exercisable, end of period, weighted-average exercise price (in USD per share)	$ 39.39	$ 38.56
Options, Additional Disclosures:
Outstanding, end of period, weighted-average remaining contractual term	7 years	7 years 2 months 12 days
Exercisable, end of period, weighted-average remaining contractual term	5 years 7 months 6 days	5 years 8 months 12 days
Outstanding, end of period, aggregate intrinsic value	$ 5,032	$ 3,959
Exercisable, end of period, aggregate intrinsic value	$ 3,430	$ 2,772