Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Mar. 31, 2018	Mar. 31, 2017
Statement of Financial Position [Abstract]
Accounts receivable, allowance for doubtful accounts	$ 12,643	$ 12,662
Preferred stock, par value (usd per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (in shares)	1,000,000	1,000,000
Preferred stock, shares issued (in shares)	0	0
Preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (usd per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	135,000,000	135,000,000
Common stock, shares issued (in shares)	54,595,105	54,370,810
Common stock, shares outstanding (in shares)	41,915,000	43,447,536
Treasury stock, shares (in shares)	12,680,105	10,923,274