CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2017	Mar. 31, 2016
Statement of Financial Position [Abstract]
Software, accumulated amortization (in dollars)	$ 314,185	$ 288,122
Purchased software licenses, accumulated amortization (in dollars)	$ 66,190	$ 72,403
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10
Common stock, authorized shares	200,000,000.0	200,000,000.0
Common stock, issued shares	136,100,000	132,900,000
Treasury stock, shares	58,300,000	54,600,000