NET INCOME PER SHARE (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Numerator:
Net income	$ 12,909	$ 3,321	$ 15,773	$ 5,535
Denominator:
Weighted average common shares outstanding - basic (in shares)	21,920,000	22,290,000	21,869,000	22,484,000
Weighted average effect of dilutive securities:
Stock options (in shares)	107,000	123,000	107,000	156,000
Restricted stock units (in shares)	252,000	142,000	277,000	201,000
Warrants (in shares)	27,000	9,000	27,000	9,000
Weighted average common shares outstanding - diluted (in shares)	22,306,000	22,564,000	22,280,000	22,850,000
Net income per share:
Basic net income per share (in dollars per share)	$ 0.59	$ 0.15	$ 0.72	$ 0.25
Diluted net income per share (in dollars per share)	$ 0.58	$ 0.15	$ 0.71	$ 0.24
Restricted Stock Units (RSUs) [Member]
Antidilutive Securities Excluded from Computation of Earnings Per Share [Line Items]
Weighted average number of shares underlying antidilutive restricted stock units (in shares)	0	264,000	101,000	219,000
Restricted stock unit awards (performance vesting) not included in the diluted net income per share calculation (in shares)			21,000