Consolidated Statements of Operations (Unaudited) (USD $)	3 Months Ended				6 Months Ended
	Jul. 31, 2013		Jul. 31, 2012		Jul. 31, 2013		Jul. 31, 2012
Consolidated Statements of Operations (Unaudited) [Abstract]
Net revenues	$ 46,186,000		$ 47,329,000		$ 91,203,000		$ 90,782,000
Cost of sales	31,719,000		34,519,000		63,206,000		66,651,000
Gross profit	14,467,000		12,810,000		27,997,000		24,131,000
Selling, general and administrative expense	11,539,000		8,667,000		21,578,000		17,079,000
Restructuring costs	1,037,000		0		1,037,000		0
Equity loss from non-consolidated subsidiary	6,000		123,000		38,000		136,000
Operating income	1,885,000		4,020,000		5,344,000		6,916,000
Other income (expense):
Interest expense, net	(1,864,000)		(922,000)		(2,655,000)		(1,799,000)
Other income (expense), net	68,000		65,000		82,000		93,000
Total other income (expense), net	(1,796,000)		(857,000)		(2,573,000)		(1,706,000)
Income before income taxes and noncontrolling interests	89,000		3,163,000		2,771,000		5,210,000
Income taxes	38,000		1,313,000		1,104,000		2,146,000
Net income from continuing operations	51,000		1,850,000		1,667,000		3,064,000
Loss from discontinued operations, net of tax	0		(12,000)		0		(4,000)
Net income	51,000		1,838,000		1,667,000		3,060,000
Net income attributable to noncontrolling interests	(195,000)		(236,000)		(380,000)		(504,000)
Net (loss) income attributable to NTS	(144,000)		1,602,000		1,287,000		2,556,000
Net (loss) income from continuing operations attributable to NTS	(144,000)		1,614,000		1,287,000		2,560,000
Net loss from discontinued operations attributable to NTS	$ 0		$ (12,000)		$ 0		$ (4,000)
Basic earnings attributable to NTS per common share:
Net (loss) income from continuing operations	$ (0.01)		$ 0.14		$ 0.11		$ 0.23
Net loss from discontinued operations	$ 0		$ 0		$ 0		$ 0
Net (loss) income attributable to NTS	$ (0.01)	[1]	$ 0.14	[1]	$ 0.11	[1]	$ 0.23	[1]
Diluted earnings attributable to NTS per common share:
Net (loss) income from continuing operations	$ (0.01)		$ 0.14		$ 0.11		$ 0.22
Net loss from discontinued operations	$ 0		$ 0		$ 0		$ 0
Net (loss) income attributable to NTS	$ (0.01)	[1]	$ 0.13	[1]	$ 0.11	[1]	$ 0.22	[1]
Weighted average common shares outstanding	11,598,000		11,340,000		11,544,000		11,330,000
Dilutive effect of stock options, nonvested shares and warrants	611,000		552,000		621,000		531,000
Weighted average common shares outstanding, assuming dilution	12,209,000		11,892,000		12,165,000		11,861,000

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