Stock Incentive Compensation and Employee Benefit Plans (Tables)

12 Months Ended

Dec. 31, 2015

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

Schedule of Share-based Payment Award, Performance Shares, Valuation Assumptions

The following are the weighted average-assumptions used to estimate the fair value for all Performance Shares issued in each respective year.




	Performance Shares
Year ended December 31,	2015	2014
Expected volatility (1)	14.3% - 14.4%	14.5% - 18.6%
Expected term (in years)	n/a	n/a
Expected dividend yield	n/a	n/a
Risk-free interest rate (1)	0.07% - 1.02%	0.08% - 1.65%


(1)	The expected volatility and risk-free interest rate applied are specific to each tranche of Performance Shares.

Schedule of Share-based Compensation, 2001 Stock Incentive Plan, Non-Employee Director Stock Incentive Plan and Premium Option Plan

Premium Option Plan




	Weighted options outstanding		Weighted average exercise price		Weighted average remaining contractual life	Aggregate intrinsic value		Range of exercise prices
Balance, December 31, 2012	842,000		$	73.82		$	6,265	$73.06 - $74.24
Options granted	—		—
Options forfeited	—		—
Options expired	—		—
Options exercised	(270,000	)	74.24			4,921
Balance, December 31, 2013	572,000		$	73.62		$	13,567	$73.06 - $74.24
Options granted	—		—
Options forfeited	—		—
Options expired	—		—
Options exercised	(572,000	)	73.62			13,414
Balance, December 31, 2014	—		$	—		$	—	$	—
Options granted	—		—
Options forfeited	—		—
Options expired	—		—
Options exercised	—		—			—
Balance, December 31, 2015	—		$	—	0.0	$	—	$	—
Total options exercisable at December 31, 2015	—		$	—	0.0	$	—	$	—

2001 Stock Incentive and Non-Employee Director Stock Incentive Plans




	Weighted options outstanding		Weighted average exercise price		Weighted average remaining contractual life	Aggregate intrinsic value		Range of exercise prices
Balance, December 31, 2012	1,732,639		$	47.61	3.7	$	58,305	$37.51 - $59.66
Options granted	—		—					—
Options forfeited	—		—
Options expired	—		—
Options exercised	(904,547	)	46.55			$	36,800
Balance, December 31, 2013	828,092		$	48.77	2.9	$	40,221	$37.51 - $59.66
Options granted	—		—					—
Options forfeited	—		—
Options expired	—		—
Options exercised	(60,262	)	49.52			$	2,900
Balance, December 31, 2014	767,830		$	48.71	2.0	$	37,246	$37.51 - $59.66
Options granted	—		—					—
Options forfeited	—		—
Options expired	—		—
Options exercised	(359,618	)	$	45.09		$	21,205
Balance, December 31, 2015	408,212		$	51.90	1.6	$	25,020	$42.66 - $59.66
Total options exercisable at December 31, 2015	408,212		$	51.90	1.6	$	25,020	$42.66 - $59.66

Schedule of Share-based Compensation, 2010 Cash Settled Restricted Stock Unit Plan and 2010 Performance-Based Equity Incentive Plan

2010 Cash Settled Restricted Stock Unit Plan and 2010 Performance-Based Equity Incentive Plan




	Cash Settled Restricted Stock Units		Performance Shares (1)
	Number of shares		Number of shares		Weighted average grant-date fair value
Nonvested at December 31, 2012	493,556		359,520		$	29.46
Awards granted	149,760		134,358		$	33.46
Awards vested	(176,265	)	(24,606	)
Awards forfeited	(72,906	)	(109,729	)
Nonvested at December 31, 2013	394,145		359,543		$	30.55
Awards granted	119,382		102,668		$	46.45
Awards vested	(159,094	)	—
Awards forfeited	(16,110	)	(213,639	)
Nonvested at December 31, 2014	338,323		248,572		$	39.62
Awards granted	160,817		103,024		$	44.98
Awards vested	(144,440	)	—
Awards forfeited	(28,622	)	(121,325	)
Nonvested at December 31, 2015	326,078		230,271		$	41.40

(1) For Performance Shares, the number of shares is stated at the maximum number that can be attained if the performance conditions are fully met. Forfeitures represent shares forfeited due to vesting below the maximum attainable as a result of the Company not fully meeting the performance conditions.

Schedule of Share-based Compensation, Restricted Stock

Restricted Stock Awards




	Employee restricted stock awards				Non-employee director restricted stock awards				Total restricted stock awards
	Number of shares		Weighted average grant date fair value		Number of shares		Weighted average grant date fair value		Number of shares		Weighted average grant date fair value
Nonvested at December 31, 2012	646,748		$	61.63	35,923		$	66.83	682,671		$	61.90
Awards granted	241,071		87.85		17,162		87.40		258,233		87.82
Awards vested	(311,334	)	55.63		(21,599	)	66.06		(332,933	)	56.31
Awards forfeited	(6,993	)	58.14		—		—		(6,993	)	58.14
Nonvested at December 31, 2013	569,492		$	76.11	31,486		$	78.57	600,978		$	76.24
Awards granted	215,054		95.79		14,455		95.06		229,509		95.74
Awards vested	(332,725	)	73.74		(15,886	)	74.96		(348,611	)	73.79
Awards forfeited	(99	)	55.80		—		—		(99	)	55.80
Nonvested at December 31, 2014	451,722		$	87.29	30,055		$	88.41	481,777		$	87.36
Awards granted	195,337		102.17		14,575		102.90		209,912		102.22
Awards vested	(168,019	)	82.75		(17,744	)	86.37		(185,763	)	83.10
Awards forfeited	—		—		—		—		—		—
Nonvested at December 31, 2015	479,040		$	94.95	26,886		$	97.61	505,926		$	95.09