CONDENSED CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2017	Mar. 31, 2017
Statement of Financial Position [Abstract]
Trade accounts receivable, allowances (in dollars)	$ 41,913	$ 32,354
Inventory reserves	8,320	7,638
Accumulated depreciation	200,789	190,758
Accumulated amortization	$ 63,776	$ 56,944
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, authorized shares (in shares)	125,000,000	125,000,000
Common stock, issued shares (in shares)	31,758,000	31,987,000
Common stock, outstanding shares (in shares)	31,758,000	31,987,000