Equity Based Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2012

Equity Based Compensation Plans [Abstract]

Weighted average assumptions used to estimate fair value of stock options

The average fair value of stock options granted for the years ended December 31, 2012, 2011 and 2010 was $12.64, $14.49 and $18.39, respectively.  The stock options granted during the fourth quarter of 2012 included a $75 cap on the appreciation of the market price over the exercise price.  The stock options granted during 2011 and through the third quarter of 2012 included a $100 cap on the appreciation of the market price over the exercise price.  The fair value of stock options was estimated on the date of grant using the Black-Scholes option pricing model with the following weighted average assumptions used for grants:

	2012	2011	2010
Stock price	$143.95	$131.87	$107.21
Risk-free interest rates	1.16%	2.23%	3.50%
Expected lives	5 - 10 years	10 years	10 years
Volatility	20.05%	19.63%	22.00%
Dividend yield	3.26%	3.29%	3.85%

Summary of stock options activity

A summary of the status of the Company's stock option plans as of December 31, 2012, 2011, and 2010 and changes during the years ended on those dates is presented below:

	2012					2011					2010
				Weighted-					Weighted-					Weighted-
				average					average					average
				exercise					exercise					exercise
	Shares			price		Shares			price		Shares			price
Outstanding at beginning of year		415,020		$	109.71		300,642		$	88.11		378,542		$	82.08
Granted		263,113			143.95		197,500			131.87		18,214			107.21
Exercised		(41,603	)		77.21		(83,122	)		84.24		(78,381	)		63.97
Forfeited and canceled		(13,096	)		128.36		-			0.00		(17,733	)		105.40
Outstanding at end of year		623,434			125.96		415,020			109.71		300,642			88.11
Options exercisable at year end		250,620			107.12		219,820			92.31		265,770			86.28

Summary information of stock options outstanding

The following table summarizes information about stock options outstanding as of December 31, 2012:

	Options outstanding					Options exercisable
	Number		Weighted-			Number
	outstanding		average	Weighted-		exercisable		Weighted-
	as of		remaining	average		as of		average
Range of	December 31,		contractual	exercise		December 31,		exercise
exercise prices	2012		life	price		2012		price
$51.01 - 79.05		34,973	3.0 years	$	69.97		34,973	$	69.97
79.25 - 125.84		144,498	3.9 years		99.10		130,498		98.69
126.73 - 155.34		443,963	7.9 years		139.10		85,149		135.31
		623,434	6.7 years		125.96		250,620		107.12

Restricted stock activity

The following table summarizes information about restricted stock outstanding as of December 31, 2012, 2011 and 2010 and changes during the years ended:

	2012					2011					2010
				Weighted-					Weighted-					Weighted-
				average					average					average
				grant					grant					grant
	Shares			price		Shares			price		Shares			price
Unvested at beginning of year		35,219		$	98.57		44,877		$	102.46		37,727		$	99.43
Granted		1,614			149.68		1,540			134.44		14,415			109.62
Vested		(8,641	)		106.69		(9,532	)		104.91		(6,126	)		102.27
Forfeited and canceled		(3,270	)		102.00		(1,666	)		94.35		(1,139	)		93.92
Unvested at end of year		24,922			104.52		35,219			98.57		44,877			102.46

Summary of long term incentive plan - Z Units

The following table summarizes information about the Z Units outstanding as of December 31, 2012 ($ in thousands):

	Long Term Incentive Plan - Z Units
							Aggregate							Weighted-
							Intrinsic					Weighted-		average
	Total			Total			Value		Total			average		Remaining
	Vested			Unvested			of Unvested		Outstanding			Grant-date		Contractual
	Units			Units			Units		Units			Fair Value		Life
Balance, December 2009		288,651			105,881		$	8,751		394,532		$	39.36	8.2 years
Granted		-			108,000					108,000
Vested		37,629			(37,629	)				-
Cancelled					(4,350	)				(4,350	)
Balance, December 2010		326,280			171,902			19,463		498,182			54.15	11.2 years
Granted		-			46,500					46,500
Vested		44,520			(44,520	)				-
Converted		(191,718	)		-					(191,718	)
Cancelled		-			(3,863	)				(3,863	)
Balance, December 2011		179,082			170,019			23,719		349,101			58.17	12.3 years
Granted		-			-					-
Vested		28,163			(28,163	)				-
Converted		(16,541	)		-					(16,541	)
Cancelled		-			(1,813	)				(1,813	)
Balance, December 2012		190,704			140,043		$	20,800		330,747		$	58.44	11.3 years