Unaudited Consolidated Statements of Income (USD $)	3 Months Ended		6 Months Ended
	Jul. 31, 2011	Jul. 31, 2010	Jul. 31, 2011	Jul. 31, 2010
Unaudited Consolidated Statements of Income [Abstract]
Net revenues	$ 37,955,000	$ 34,525,000	$ 75,465,000	$ 70,657,000
Cost of sales	28,900,000	25,212,000	57,144,000	50,560,000
Gross profit	9,055,000	9,313,000	18,321,000	20,097,000
Selling, general and administrative expense	6,811,000	7,323,000	14,606,000	14,765,000
Equity loss from non-consolidated subsidiary	24,000	30,000	3,000	47,000
Operating income	2,220,000	1,960,000	3,712,000	5,285,000
Other income (expense):
Interest expense, net	(548,000)	(287,000)	(839,000)	(583,000)
Other (expense) income, net	(91,000)	198,000	(41,000)	3,189,000
Total other income (expense), net	(639,000)	(89,000)	(880,000)	2,606,000
Income before income taxes and noncontrolling interests	1,581,000	1,871,000	2,832,000	7,891,000
Income taxes	632,000	749,000	1,158,000	3,151,000
Net income	949,000	1,122,000	1,674,000	4,740,000
Net income attributable to noncontrolling interests	(213,000)	(129,000)	(378,000)	(201,000)
Net income attributable to NTS	$ 736,000	$ 993,000	$ 1,296,000	$ 4,539,000
Net income attributable to NTS per common share:
Basic (in dollars per share)	$ 0.07	$ 0.10	$ 0.12	$ 0.47
Diluted earnings per common share
Diluted (in dollars per share)	$ 0.07	$ 0.10	$ 0.12	$ 0.45
Weighted average common shares outstanding - basic (in shares)	10,616,000	9,705,000	10,429,000	9,585,000
Dilutive effect of stock options, nonvested shares and warrants (in shares)	395,000	577,000	404,000	575,000
Weighted average common shares outstanding - diluted (in shares)	11,011,000	10,282,000	10,833,000	10,160,000
Cash dividends per common share	$ 0.00	$ 0.07	$ 0.00	$ 0.07