Stock Repurchase (Details) - shares	3 Months Ended	6 Months Ended
	Sep. 30, 2018	Sep. 30, 2018	Mar. 31, 2018
Equity [Abstract]
Stock repurchase program, number of shares authorized to be repurchased (in shares)	15,000,000.0	15,000,000.0
Repurchase of common stock (in shares)	0	0
Treasury stock, number of shares held (in shares)	17,024,517	17,024,517	18,205,142