Share-based Compensation (Tables)

9 Months Ended

Sep. 30, 2017

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

The fair value of each stock option or 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 nine months ended September 30, 2017 and the year ended December 31, 2016.

	September 30, 2017		December 31, 2016
Dividend yield	2.50	%	2.37	%
Expected life	4.4 years		3.7 years
Risk-free interest rate	1.73	%	1.57	%
Expected stock price volatility	28.21	%	26.76	%

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 September 30, 2017 and December 31, 2016, and changes during the nine months ended September 30, 2017 and year ended December 31, 2016 are as follows:

	September 30, 2017					December 31, 2016
	Options Outstanding			Weighted Average Exercise Price		Options Outstanding			Weighted Average Exercise Price
Balance at beginning of period	$	1,737,213		$	98.44	$	1,595,007		$	95.52
Granted	171,000			105.70		445,100			105.86
Exercised	(146,277		)	84.02		(192,875		)	76.90
Lapsed or cancelled	(65,300		)	122.30		(110,019		)	123.86
Balance at end of period	$	1,696,636		$	99.50	$	1,737,213		$	98.44
Options exercisable at end of period	939,485			$	91.71	748,617			$	87.72
Weighted average fair value of options granted during the period	$	3,775,639				$	8,363,036

Summary of restricted stock and charges during the period

A summary of the Company's restricted stock as of September 30, 2017 and December 31, 2016 and charges during the nine months ended September 30, 2017 and the year ended December 31, 2016, are as follows:

	September 30, 2017		December 31, 2016
Balance at beginning of period	3,202,031		3,137,881
Granted	300		98,800
Cancelled	—		(34,650		)
Balance at end of period	3,202,331		3,202,031
Vested during the period	86,736		83,822
Compensation expense recorded	$	7,277,054	$	7,153,966
Weighted average fair value of restricted stock granted during the period	$	30,813	$	10,650,077