Consolidated Statements of Operations (USD $)	12 Months Ended
	Jan. 31, 2012	Jan. 31, 2011
Consolidated Statements of Income [Abstract]
Net revenues	$ 155,407,000	$ 142,381,000
Cost of sales	117,822,000	103,420,000
Gross profit	37,585,000	38,961,000
Selling, general and administrative expense	30,272,000	30,897,000
Impairment loss	2,208,000	0
Equity loss from non-consolidated subsidiary	29,000	269,000
Operating income	5,076,000	7,795,000
Other income (expense):
Interest expense, net	(2,465,000)	(1,219,000)
Other income, net	1,238,000	3,961,000
Total other income (expense), net	(1,227,000)	2,742,000
Income before income taxes and noncontrolling interests	3,849,000	10,537,000
Income taxes	2,111,000	4,676,000
Net income from continuing operations	1,738,000	5,861,000
Loss from discontinued operations, net of tax	(381,000)	(78,000)
Net income	1,357,000	5,783,000
Net income attributable to noncontrolling interests	(866,000)	(433,000)
Net income attributable to NTS	491,000	5,350,000
Net income from continuing operations attributable to NTS	872,000	5,428,000
Net loss from discontinued operations attributable to NTS	$ (381,000)	$ (78,000)
Basic earnings attributable to NTS per common share:
Income from continuing operations	$ 0.08	$ 0.55
Loss from discontinued operations	$ (0.04)	$ (0.01)
Net income attributable to NTS	$ 0.05	$ 0.54
Diluted earnings attributable to NTS per common share:
Income from continuing operations	$ 0.08	$ 0.52
Loss from discontinued operations	$ (0.03)	$ (0.01)
Net income attributable to NTS	$ 0.04	$ 0.51
Weighted average common shares outstanding - basic (in shares)	10,865,000	9,861,000
Dilutive effect of stock options, nonvested shares and warrants (in shares)	374,000	535,000
Weighted average common shares outstanding, assuming dilution (in shares)	11,239,000	10,396,000
Cash dividends per common share	$ 0	$ 0.07