CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2019	Mar. 31, 2018
Statement of Financial Position [Abstract]
Accounts receivable, allowances	$ 995	$ 54,290
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)	134,602,000	132,743,000
Common stock, shares outstanding (in shares)	112,181,000	114,038,000
Treasury stock, shares (in shares)	22,421,000	18,705,000