STOCK COMPENSATION PLANS (Tables)

12 Months Ended

Dec. 31, 2012

Disclosure of Compensation Related Costs, Share-based Payments [Abstract]

Total Stock-Based Compensation Expense

	2012
	Total		NVE		NPC		SPPC
Non-Qualified Stock Options	$	-	$	-	$	-	$	-
Performance Units and Performance Shares		21,684		277		14,967		6,440
Restricted Stock Units		3,552		74		2,501		977
Employee Stock Purchase Plan		294		9		212		73
Total Stock Compensation Expense	$	25,530	$	360	$	17,680	$	7,490

	2011
	Total		NVE		NPC		SPPC
Non-Qualified Stock Options	$	-	$	-	$	-	$	-
Performance Units and Performance Shares		16,523		163		10,438		5,922
Restricted Stock Units		2,151		35		1,492		624
Employee Stock Purchase Plan		327		18		215		94
Total Stock Compensation Expense	$	19,001	$	216	$	12,145	$	6,640

	2010
	Total		NVE		NPC		SPPC
Non-Qualified Stock Options	$	71	$	1	$	51	$	19
Performance Units and Performance Shares		7,145		54		4,966		2,125
Restricted Stock Units		902		10		610		282
Employee Stock Purchase Plan		376		28		134		214
Total Stock Compensation Expense	$	8,494	$	93	$	5,761	$	2,640

Schedule of Share-based Compensation, Stock Options, Activity [Table Text Block]

		2012				2011				2010
				Weighted-				Weighted-				Weighted-
				Average				Average				Average
				Exercise				Exercise				Exercise
		Shares		Price		Shares		Price		Shares		Price
NQSO’s outstanding at beginning of year			539,450	$	16.56		728,688	$	15.50		854,717	$	15.40
	Granted		-	$	-		-	$	-		-	$	-
	Exercised		(134,601)	$	12.80		(118,175)	$	10.26		(44,730)	$	8.83
	Forfeited		(48,412)	$	14.99		(71,063)	$	16.64		(81,299)	$	18.18
NQSO’s outstanding at end of year			356,437	$	17.90		539,450	$	16.56		728,688	$	15.50
Options exercisable at year-end		$	356,437	$	17.90	$	539,450	$	16.56	$	728,688	$	15.50
Intrinsic value of options exercised		$	660,530	$	-	$	545,695	$	-	$	146,102	$	-

	Options Outstanding				Options Exercisable
	Weighted-				Weighted-		Number
	Average		Number	Remaining	Average		Vested and
	Exercise		Outstanding at	Contractual	Exercise		Exercisable at
Year of Grant	Price		12/31/12	Life	Price		12/31/12
2005	$	10.05	6,599	2.1 years	$	10.05	6,599
2006	$	13.29	23,233	3.1 years	$	13.29	23,233
2007	$	18.38	326,605	4.1-4.8 years	$	18.38	326,605
Weighted Average Remaining
Contractual Life (years)		4.15				4.15
Intrinsic Value	$	166,066			$	166,066

Vesting Schedule for Performance Units

Performance	Shares Vested
Below 35th Percentile	0% of grant
35th Percentile	50% of grant
50th Percentile	100% of grant
75th Percentile	150% of grant

Schedule of Nonvested Performance-based Units Activity [Table Text Block]

		2012				2011					2010
				Weighted-				Weighted-				Weighted-
				Average				Average				Average
				Grant Date				Grant Date				Grant Date
			Shares	Value			Shares	Value			Shares	Value
Nonvested performance units and
performance shares at beginning of year			652,184	$	13.64		763,386	$	11.47		765,143	$	11.73
	Shares granted		1,380,621	$	17.37		890,252	$	15.18		753,612	$	11.78
	Shares vested		(1,126,932)	$	15.91		(958,750)	$	13.40		(666,856)	$	12.08
	Shares forfeited		(53,635)	$	13.99		(42,704)	$	12.51		(88,513)	$	11.81
Nonvested performance units and
performance shares at end of year			852,238	$	15.90		652,184	$	13.64		763,386	$	11.47
Weighted average grant date fair value of shares granted		$	23,977,660			$	13,514,025			$	8,877,549
Fair value of shares issued		$	16,793,342			$	5,441,944			$	-
Unrecognized compensation expense at end of year		$	15,459,606			$	10,663,208			$	10,725,573
Weighted average remaining vesting period (years)			1.67				1.63				1.65

Schedule of Share-based Compensation, Restricted Stock Units Award Activity [Table Text Block]

		2012				2011				2010
				Weighted-				Weighted-				Weighted-
				Average				Average				Average
				Grant Date				Grant Date				Grant Date
		Shares		Value		Shares		Value		Shares		Value
Nonvested shares at beginning of year			289,210	$	13.77		149,779	$	11.54		64,667	$	11.41
	Shares granted		169,000	$	17.05		267,750	$	14.51		169,000	$	11.65
	Shares vested		(175,009)	$	14.31		(123,413)	$	12.76		(75,708)	$	11.73
	Shares forfeited		(7,500)	$	14.32		(4,906)	$	11.58		(8,180)	$	11.14
Nonvested shares at end of year			275,701	$	15.43		289,210	$	13.77		149,779	$	11.54
Weighted average grant date fair value of shares granted		$	2,882,200			$	3,885,053			$	1,968,850
Fair value of shares issued		$	904,135			$	671,162			$	-
Unrecognized compensation expense at end of year		$	5,001,210			$	4,728,581			$	2,104,393
Weighted average remaining vesting period (years)			1.96				2.55				2.14

Schedule of Share-based Payment Award, Employee Stock Purchase Plan, Valuation Assumptions [Table Text Block]

			Average
	Average	Average	Risk-Free	Weighted-
	Dividend	Expected	Rate of	Average
Year	Yield	Volatility	Return	Fair Value
2011	3.42%	13.99%	0.11%	$	2.82
2010	2.79%	20.02%	0.22%	$	2.55