QUARTERLY INFORMATION (Unaudited) (Details) - USD ($) $ / shares in Units, $ in Thousands	3 Months Ended								12 Months Ended
	Jan. 31, 2016	Oct. 31, 2015	Jul. 31, 2015	Apr. 30, 2015	Jan. 31, 2015	Oct. 31, 2014	Jul. 31, 2014	Apr. 30, 2014	Jan. 31, 2016	Jan. 31, 2015	Jan. 31, 2014
Class of Stock [Line Items]
Total revenue	$ 69,259	$ 68,037	$ 71,291	$ 69,265	$ 79,562	$ 74,004	$ 73,050	$ 68,485	$ 277,852	$ 295,101	$ 266,311
Total costs and expenses	65,638	64,570	68,968	68,505	71,828	68,115	70,986	68,187
Gross margin	38,428	37,032	38,663	37,167	45,653	40,933	39,831	37,054	151,290	163,471	149,305
Operating income	3,621	3,467	2,323	760	7,734	5,889	2,064	298	10,171	15,985	9,403
Net income (loss)	$ 4,146	$ 2,586	$ 1,631	$ 549	$ 6,947	$ 5,090	$ 985	$ (76)	8,912	12,946	6,386
Common Class A [Member]
Class of Stock [Line Items]
Net income (loss)									$ 7,606	$ 10,729	$ 5,282
Basic net income (loss) per share (in dollars per share)	$ 0.23	$ 0.14	$ 0.09	$ 0.03	$ 0.44	$ 0.33	$ 0.06	$ (0.01)	$ 0.49	$ 0.84	$ 0.42
Diluted net income (loss) per share (in dollars per share)	0.19	0.12	0.08	0.03	0.42	0.31	0.06	(0.01)	$ 0.47	$ 0.79	$ 0.41
Common Class B [Member]
Class of Stock [Line Items]
Net income (loss)									$ 1,306	$ 2,217	$ 1,104
Basic net income (loss) per share (in dollars per share)	0.22	0.14	0.09	0.03	0.37	0.27	0.05	0	$ 0.41	$ 0.70	$ 0.35
Diluted net income (loss) per share (in dollars per share)	$ 0.18	$ 0.12	$ 0.07	$ 0.02	$ 0.36	$ 0.27	$ 0.05	$ 0	$ 0.40	$ 0.68	$ 0.34