Consolidated Statements of Operations (USD $)	12 Months Ended
	Jan. 31, 2013		Jan. 31, 2012
Consolidated Statements of Operations [Abstract]
Net revenues	$ 184,547,000		$ 155,407,000
Cost of sales	135,839,000		117,822,000
Gross profit	48,708,000		37,585,000
Selling, general and administrative expense	35,779,000		30,272,000
Impairment loss	0		2,208,000
Equity loss from non-consolidated subsidiary	235,000		29,000
Operating income	12,694,000		5,076,000
Other income (expense):
Interest expense, net	(3,471,000)		(2,465,000)
Other income, net	1,027,000		1,238,000
Total other income (expense), net	(2,444,000)		(1,227,000)
Income before income taxes and noncontrolling interests	10,250,000		3,849,000
Income taxes	4,827,000		2,111,000
Net income from continuing operations	5,423,000		1,738,000
Loss from discontinued operations, net of tax	(3,000)		(381,000)
Net income	5,420,000		1,357,000
Net income attributable to noncontrolling interests	(976,000)		(866,000)
Net income attributable to NTS	4,444,000		491,000
Net income from continuing operations attributable to NTS	4,447,000		872,000
Net loss from discontinued operations attributable to NTS	$ (3,000)		$ (381,000)
Basic earnings attributable to NTS per common share:
Net income from continuing operations (in dollars per share)	$ 0.39		$ 0.08
Net loss from discontinued operations (in dollars per share)	$ 0		$ (0.04)
Net income attributable to NTS * (in dollars per share)	$ 0.39	[1]	$ 0.05	[1]
Diluted earnings attributable to NTS per common share:
Net income from continuing operations attributable to NTS (in dollars per share)	$ 0.37		$ 0.08
Net loss from discontinued operations (in dollars per share)	$ 0		$ (0.03)
Net income attributable to NTS * (in dollars per share)	$ 0.37	[1]	$ 0.04	[1]
Weighted average common shares outstanding (in shares)	11,376,000		10,865,000
Dilutive effect of stock options, nonvested shares and warrants (in shares)	576,000		374,000
Weighted average common shares outstanding, assuming dilution (in shares)	11,952,000		11,239,000

[1] Per share data may not always add to the total for the year because each figure is independently calculated.