CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Mar. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Allowances for accounts receivable	$ 3,098	$ 1,576	$ 1,888
Preferred stock, par value (in dollars per share)	$ 0.01	$ 0.01	$ 0.01
Preferred stock, shares authorized	1,000,000	1,000,000	1,000,000
Preferred stock, shares issued	0	0	0
Common stock, par value (in dollars per share)	$ 0.10	$ 0.10	$ 0.10
Common stock, shares authorized	25,000,000	25,000,000	25,000,000
Common stock, shares issued	14,703,084	14,703,084	14,703,084
Treasury stock, shares	5,867,184	5,583,338	5,583,338