Stock Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2012

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

Stock Compensation

	2012		2011		2010
Stock-based compensation expense	$	5,792	$	5,756	$	4,916
Income tax benefits	2,027		2,014		1,720

Stock Options Activity

	2012			2011			2010
Number of shares under stock options:
Options outstanding at beginning of year	92,499			201,674			523,973
Options granted	—			—			—
Options exercised	(89,499		)	(107,575		)	(101,649		)
Options canceled	—			(1,600		)	(220,650		)
Options outstanding and exercisable at end of year	3,000			92,499			201,674
Weighted average exercise price:
Options exercised	$	10.63		$	12.25		$	11.51
Options canceled	$	—		$	11.80		$	22.60
Options outstanding and exercisable at end of year	$	12.41		$	10.69		$	11.53
Cash received from options exercised (in thousands)	$	951		$	1,318		$	2,179
Intrinsic value of options exercised (in thousands)	$	1,349		$	1,279		$	1,006
Intrinsic value of options outstanding (in thousands)	$	35		$	1,393		$	2,217

Options Outstanding and Exercisable

Exercise Price	Number of Shares	Weighted Average Exercise Price	Weighted Average Remaining Life (in years)
$12.41	3,000	12.41	0.35

Restricted Stock Activity

	2012			2011			2010
Unvested shares at beginning of year	93,482			84,134			71,904
Shares granted	70,281			50,618			43,800
Shares canceled	(790		)	(431		)	—
Shares vested	(45,855		)	(40,839		)	(31,570		)
Unvested shares at end of year	117,118			93,482			84,134
Weighted average fair value at grant date	$	25.83		$	23.06		$	19.80
Unrecognized compensation expense at end of year (in thousands)	$	1,428		$	932		$	735
Intrinsic value, unvested shares at end of year (in thousands)	$	2,824		$	2,407		$	1,895
Intrinsic value, shares vested during the year (in thousands)	$	1,173		$	934		$	682

Estimated Fair Value of Performance Shares Granted

	2012			2011			2010
Risk-free interest rate	0.3		%	1.2		%	1.4		%
Expected life, in years	3			3			3
Expected volatility	22.7		%	26.9		%	27.8		%
Dividend yield	4.5		%	4.7		%	4.6		%
Weighted average grant date fair value (per share)	$	26.06		$	20.79		$	15.30

Performance Share Activity

	2012			2011			2010
Opening balance of unvested performance shares	351,345			325,700			300,601
Performance shares granted	181,000			184,600			168,700
Performance shares canceled	(4,544		)	(2,177		)	—
Performance shares vested	(168,101		)	(156,778		)	(143,601		)
Ending balance of unvested performance shares	359,700			351,345			325,700
Intrinsic value of unvested performance shares (in thousands)	$	8,672		$	9,047		$	7,335
Unrecognized compensation expense (in thousands)	$	3,800		$	2,991		$	2,330

Impact of the Market Condition on the Vested Performance Shares

	2012			2011			2010
Performance shares vested	168,101			156,778			143,601
Impact of market condition on shares vested	(168,101		)	(15,678		)	21,540
Shares of common stock earned	—			141,100			165,141
Intrinsic value of common stock earned (in thousands)	$	—		$	3,633		$	3,719

Common Stock Repurchased

	2012		2011		2010
Stock repurchased from Ecova employees	$	599	$	464	$	2,593