CONSOLIDATED STATEMENTS OF SHAREHOLDERS' EQUITY - USD ($) $ in Thousands	Common Stock [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Total
Balance at Mar. 31, 2015	$ 132,559	$ 87,643	$ (8)	$ 220,194
Balance (in shares) at Mar. 31, 2015	22,539,000
Increase (Decrease) in Stockholders' Equity
Common stock issued in settlement of restricted stock units, net of shares withheld for employee taxes	$ (5,250)	0	0	(5,250)
Common stock issued in settlement of restricted stock units, net of shares withheld for employee taxes (in shares)	190,000
Warrant exercises	$ 12	0	0	12
Warrants exercises (in shares)	4,000
Repurchases of common stock, net	$ (13,040)	0	0	(13,040)
Repurchases of common stock, net (in shares)	(325,000)
Dividends to shareholders	$ 0	(9,970)	0	(9,970)
Share-based compensation	11,114	0	0	11,114
Excess tax benefits from share-based awards and other tax adjustments	1,621	0	0	1,621
Net income	0	31,630	0	31,630
Other comprehensive income (loss), net of tax	0	0	1	1
Balance at Mar. 31, 2016	$ 127,016	109,303	(7)	236,312
Balance (in shares) at Mar. 31, 2016	22,408,000
Increase (Decrease) in Stockholders' Equity
Common stock issued in settlement of restricted stock units, net of shares withheld for employee taxes	$ (2,234)	0	0	(2,234)
Common stock issued in settlement of restricted stock units, net of shares withheld for employee taxes (in shares)	132,000
Dividends to shareholders	$ 0	(11,715)	0	(11,715)
Share-based compensation	11,126	0	0	11,126
Excess tax benefits from share-based awards and other tax adjustments	24	0	0	24
Net income	0	32,716	0	32,716
Other comprehensive income (loss), net of tax	0	0	(5)	(5)
Balance at Mar. 31, 2017	$ 135,932	130,304	(12)	266,224
Balance (in shares) at Mar. 31, 2017	22,540,000
Increase (Decrease) in Stockholders' Equity
Common stock issued in settlement of restricted stock units, net of shares withheld for employee taxes	$ (2,590)	0	0	(2,590)
Common stock issued in settlement of restricted stock units, net of shares withheld for employee taxes (in shares)	158,000
Dividends to shareholders	$ 0	(13,611)	0	(13,611)
Share-based compensation	13,658	0	0	13,658
Net income	0	27,177	0	27,177
Other comprehensive income (loss), net of tax	0	0	(165)	(165)
Balance at Mar. 31, 2018	$ 147,000	$ 143,870	$ (177)	$ 290,693
Balance (in shares) at Mar. 31, 2018	22,698,000