CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2018	Mar. 31, 2018
Statement of Financial Position [Abstract]
Accounts receivable, allowances (in dollars)	$ 350	$ 54,290
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized	5,000,000	5,000,000
Preferred stock, shares issued	0	0
Preferred stock, shares outstanding	0	0
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	133,811,000	132,743,000
Common stock, shares outstanding	113,509,000	114,038,000
Treasury stock, shares	20,302,000	18,705,000