Stock-Based Compensation (Tables)

12 Months Ended

Dec. 31, 2011

Notes to Financial Statements [Abstract]

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

	Years ended December 31,
	2011	2010	2009
Expected volatility	32.83% to 35.60%	32.79% to 34.98%	32.22% to 33.69%
Expected dividend yield	2.45%	2.45% to 2.47%	2.37% to 2.45%
Risk-free interest rate	1.58% to 2.41%	1.78% to 2.40%	2.34% to 2.72%
Expected life	4.75 to 6 years	4.75 to 6 years	4.75 to 6 years

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

		Third Amended 2003 Plan			1992 Plan
			Weighted-			Weighted-
		Shares	Average		Shares	Average
		Under	Exercise		Under	Exercise
		Option	Price		Option	Price
Outstanding December 31, 2008		2,311,111	$	20.61	312,109	$	13.70
	Granted	752,433		20.72	-		-
	Exercised	(14,889)		16.83	(263,090)		13.52
	Forfeited	(34,435)		17.39	-		-
Outstanding December 31, 2009		3,014,220	$	20.69	49,019	$	14.65
	Granted	684,635		24.90	-		-
	Exercised	(91,044)		19.48	(9,860)		14.65
	Forfeited	(10,940)		25.60	-		-
Outstanding December 31, 2010		3,596,871	$	21.51	39,159	$	14.65
	Granted	75,271		28.49	-		-
	Exercised	(77,386)		17.22	(29,188)		14.65
	Forfeited	(510)		24.06	(9,971)		14.65
Outstanding December 31, 2011		3,594,246	$	21.75	-	$	-
Exercisable December 31, 2009		1,229,447	$	20.70	49,019	$	14.65
Exercisable December 31, 2010		1,814,539		19.83	39,159		14.65
Exercisable December 31, 2011		2,478,000		19.86	-		-

Schedule of Share-based Compensation, Shares Authorized under Stock Option Plans, by Exercise Price Range [Table Text Block]

		Options Outstanding				Options Exercisable
Range of Exercise Prices		Number of Options	Weighted-Average Remaining Contractual Life		Weighted-Average Exercise Price	Number of Options		Weighted-Average Exercise Price
Third Amended 2003 Plan:
	12.55 - 15.00	792,934	6.96years	$	12.55	792,934	$	12.55
	15.01 - 20.00	205,573	4.78years		16.90	205,573		16.90
	20.01 - 25.00	1,726,790	7.00years		23.28	1,127,284		23.04
	25.01 - 28.49	868,949	6.47years		28.23	352,209		27.85
		3,594,246	6.73years	$	21.75	2,478,000	$	19.86

Schedule of Share-based Compensation, Stock Appreciation Rights Award Activity [Table Text Block]

		Third Amended 2003 Plan
			Weighted-Average
		SARs	Exercise Price
Outstanding December 31, 2008		1,200,552	$	18.02
	Granted	417,647		21.64
	Exercised	(50,174)		12.55
	Forfeited	(74,894)		18.82
Outstanding December 31, 2009		1,493,131	$	19.18
	Granted	376,795		24.67
	Exercised	(47,322)		12.64
	Forfeited	(38,648)		19.93
Outstanding December 31, 2010		1,783,956	$	20.50
	Granted	4,276		28.10
	Exercised	(77,477)		15.33
	Forfeited	(47,415)		25.33
Outstanding December 31, 2011		1,663,340	$	20.63
Exercisable December 31, 2009		494,775	$	22.06
Exercisable December 31, 2010		900,965		20.53
Exercisable December 31, 2011		1,278,950		19.71

SARs Exercise Price Range Table [Text Block]

	SARs Outstanding				SARs Exercisable
Range of Exercise Prices	Number of SARs	Weighted-Average Remaining Contractual Life	Weighted-Average Exercise Price		Number of SARs	Weighted-Average Exercise Price
12.55 - 17.50	568,685	6.96years	$	12.55	568,685	$	12.55
17.51 - 25.00	745,401	8.44years		23.17	365,287		22.68
25.01 - 28.48	349,254	5.71years		28.35	344,978		28.36
	1,663,340	7.36years	$	20.63	1,278,950	$	19.71

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

		Number of
		Restricted Stock		Weighted-Average
		Equity Units		Grant Date
		Outstanding		Fair Value
Restricted shares at December 31, 2008		363,185	$	18.94
	Granted	165,567		20.24
	Released	(146,990)		19.90
	Forfeited	(2,788)		18.98
Restricted shares at December 31, 2009		378,974	$	19.14
	Granted	111,457		23.71
	Released	(148,218)		17.63
	Forfeited	(1,000)		25.15
Restricted shares at December 31, 2010		341,213	$	21.27
	Granted	7,000		28.04
	Released	(162,362)		17.96
	Forfeited	-		-
Restricted shares at December 31, 2011		185,851	$	24.41

Restricted Stock Units Activity Table [Text Block]

		Number of	Weighted-Average
		Restricted Stock Liability	Grant Date
		Units Outstanding	Fair Value
Restricted units at December 31, 2008		548,639	$	17.31
	Granted	268,027		21.06
	Released	(204,937)		19.38
	Forfeited	(48,079)		16.87
Restricted units at December 31, 2009		563,650	$	18.38
	Granted	175,043		24.67
	Released	(237,219)		18.82
	Forfeited	(54,344)		18.77
Restricted units at December 31, 2010		447,130	$	20.56
	Granted	270,835		42.01
	Released	(239,714)		18.53
	Forfeited	(17,394)		18.86
Restricted units at December 31, 2011		460,857	$	34.29