Condensed Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Mar. 31, 2019
Statement Of Financial Position [Abstract]
Allowance for doubtful accounts receivable	$ 632	$ 788
Common stock, stated value	$ 0.30	$ 0.30
Common stock, shares authorized	80,000,000	80,000,000
Common stock, shares issued	31,606,831	31,606,831
Common stock, shares outstanding	23,658,529	23,501,193
Treasury shares	7,948,302	8,105,638