Stock-based Compensation (Tables)

6 Months Ended

Jun. 30, 2011

Schedule of Stock Option Transactions

		Six months ended June 30,				Three months ended June 30,
		2011		2010		2011		2010
Stock-based compensation for stock options
within operations and maintenance expenses	$	769	$	1,013	$	329	$	519
Income tax benefit		420		301		46		149

Performance Share Units [Member]

Schedule of Nonvested Restricted Stock Transactions

	Number			Weighted
	of			Average
	Share Units			Fair Value
Nonvested share units at beginning of period	-		$	-
Granted	109,375			24.38
Performance criteria adjustment	14,027			24.38
Forfeited	(1,475	)		24.38
Vested	-			-
Share unit awards issued	-			-
Nonvested share units at end of period	121,927		$	24.38

Stock Options [Member]

Schedule of Stock Option Transactions

				Weighted	Weighted
				Average	Average		Aggregate
				Exercise	Remaining		Intrinsic
	Shares			Price	Life (years)		Value
Options:
Outstanding at beginning of period	3,839,197		$	19.54
Granted	-
Forfeited	(12,356	)		18.56
Expired	(10,796	)		23.13
Exercised	(357,703	)		15.56
Outstanding at end of period	3,458,342		$	19.95	5.4	$	10,975
Exercisable at end of period	2,973,498		$	20.28	4.9	$	8,997

Restricted Stock Units (RSUs) [Member]

Schedule of Nonvested Restricted Stock Transactions

	Number		Weighted
	of		Average
	Stock Units		Fair Value
Nonvested stock units at beginning of period	-	$	-
Granted	44,342		22.21
Vested	-		-
Forfeited	-		-
Nonvested stock units at end of period	44,342	$	22.21

Restricted Stock [Member]

Schedule of Nonvested Restricted Stock Transactions

	Number			Weighted
	of			Average
	Shares			Fair Value
Nonvested shares at beginning of period	233,387		$	17.62
Granted	16,000			22.44
Vested	(85,204	)		18.63
Forfeited	(1,824	)		17.23
Nonvested share units at end of period	162,359		$	17.57