CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017
Statement of Financial Position [Abstract]
Accounts receivable, allowances	$ 54,290	$ 66,483
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	5,000,000	5,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	200,000,000	200,000,000
Common stock, shares issued (in shares)	132,743,000	119,813,000
Common stock, shares outstanding (in shares)	114,038,000	102,621,000
Treasury stock, shares (in shares)	18,705,000	17,192,000