Share-based Compensation (Tables)

12 Months Ended

Dec. 31, 2016

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

Schedule of weighted average assumptions used to estimate the grant date fair value of options granted

A summary of the Company's restricted stock as of December 31, 2016, 2015, and 2014 and charges during the years ended December 31, 2016, 2015, and 2014 are as follows:

	2016			2015			2014
Balance at beginning of year	3,137,881			3,000,979			2,994,197
Granted	98,800			143,053			9,550
Cancelled	(34,650		)	(6,151		)	(2,768		)
Balance at end of year	3,202,031			3,137,881			3,000,979
Vested during the year	83,822			87,081			75,043
Compensation expense recorded	$	7,153,966		$	7,540,747		$	9,658,019
Weighted average fair value of restricted stock granted during the year	$	10,650,077		$	16,061,201		$	1,141,675

The fair value of each stock option or Class O LTIP Unit granted is estimated on the date of grant using the Black-Scholes option pricing model based on historical information with the following weighted average assumptions for grants during the years ended December 31, 2016, 2015, and 2014.

	2016		2015		2014
Dividend yield	2.37	%	1.97	%	1.60	%
Expected life	3.7 years		3.6 years		3.6 years
Risk-free interest rate	1.57	%	1.43	%	1.29	%
Expected stock price volatility	26.76	%	32.34	%	33.97	%

Summary of the status of stock options and changes during the period

A summary of the status of the Company's stock options as of December 31, 2016, 2015, and 2014 and changes during the years ended December 31, 2016, 2015, and 2014 are as follows:

	2016					2015					2014
	Options Outstanding			Weighted Average Exercise Price		Options Outstanding			Weighted Average Exercise Price		Options Outstanding			Weighted Average Exercise Price
Balance at beginning of year	$	1,595,007		$	95.52	$	1,462,726		$	87.98	$	1,765,034		$	83.24
Granted	445,100			105.86		389,836			112.54		102,050			119.12
Exercised	(192,875		)	76.90		(217,438		)	74.69		(348,156		)	72.76
Lapsed or cancelled	(110,019		)	123.86		(40,117		)	98.61		(56,202		)	90.03
Balance at end of year	$	1,737,213		$	98.44	$	1,595,007		$	95.52	$	1,462,726		$	87.98
Options exercisable at end of year	748,617			$	87.72	589,055			$	89.85	$	428,951		$	90.32
Weighted average fair value of options granted during the year	$	8,363,036				$	9,522,613				$	2,841,678