Equity Based Compensation Plans (Tables)

12 Months Ended

Dec. 31, 2013

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, 2013, 2012 and 2011 was $15.80, $12.64 and $14.49, respectively. Certain stock options grated in 2013, 2012, and 2011 included a $75 cap or 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:

	2013			2012			2011
Stock price	$	153.54		$	143.95		$	131.87
Risk-free interest rates		2.68	%		1.16	%		2.23	%
Expected lives	10 years			5 - 10 years			10 years
Volatility		18.03	%		20.05	%		19.63	%
Dividend yield		3.15	%		3.26	%		3.29	%

Summary of stock options activity

A summary of the status of the Company’s stock option plans as of December 31, 2013, 2012, and 2011 and changes during the years ended on those dates is presented below:

	2013					2012					2011
				Weighted-					Weighted-					Weighted-
				average					average					average
				exercise					exercise					exercise
	Shares			price		Shares			price		Shares			price
Outstanding at beginning of year		623,434		$	125.96		415,020		$	109.71		300,642		$	88.11
Granted		150,325			153.54		263,113			143.95		197,500			131.87
Exercised		(52,970	)		102.43		(41,603	)		77.21		(83,122	)		84.24
Forfeited and canceled		(25,301	)		135.25		(13,096	)		128.36		-			-
Outstanding at end of year		695,488			133.37		623,434			125.96		415,020			109.71
Options exercisable at year end		300,632			119.09		250,620			107.12		219,820			92.31

Summary information of stock options outstanding

The following table summarizes information about stock options outstanding as of December 31, 2013:

		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		2013		life (years)		price		2013		price
$	62.34 - $101.01		74,261		2.7	$	79.18		72,261	$	79.02
	105.64 - 161.98		604,902		7.2		139.18		228,371		131.77
	164.76 - 164.76		16,325		9.4		164.76		-		-
			695,488		6.8		133.37		300,632		119.09

Restricted stock activity

The following table summarizes information about restricted stock outstanding as of December 31, 2013, 2012 and 2011 and changes during the years ended:

	2013					2012					2011
				Weighted-					Weighted-					Weighted-
				average					average					average
				grant					grant					grant
	Shares			price		Shares			price		Shares			price
Unvested at beginning of year		24,922		$	104.52		35,219		$	98.57		44,877		$	102.46
Granted		1,556			158.75		1,614			149.68		1,540			134.44
Vested		(7,211	)		109.86		(8,641	)		106.69		(9,532	)		104.91
Forfeited and canceled		(3,091	)		100.84		(3,270	)		102.00		(1,666	)		94.35
Unvested at end of year		16,176			108.06		24,922			104.52		35,219			98.57

Summary of long term incentive plan - Z Units

The following table summarizes information about the Z Units and 2014 LTIP Units outstanding as of December 31, 2013 ($ in thousands):

	Long Term Incentive Plan - Z Units and 2014 LTIP 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 (years)
Balance, December 2010		326,280			171,902		$	19,463		498,182		$	54.15		11.2
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
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
Granted		-			50,500					50,500
Vested		35,919			(35,919	)				-
Converted		(108,433	)		-					(108,433	)
Cancelled		-			(5,243	)				(5,243	)
Balance, December 2013		118,190			149,381		$	21,438		267,571		$	63.53		9.3