Share-based Compensation (Tables)

6 Months Ended

Jun. 30, 2018

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 six months ended June 30, 2018 and the year ended December 31, 2017.

	June 30, 2018		December 31, 2017
Dividend yield	2.85	%	2.51	%
Expected life	3.5 years		4.4 years
Risk-free interest rate	2.48	%	1.73	%
Expected stock price volatility	22.00	%	28.10	%

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 June 30, 2018 and December 31, 2017, and changes during the six months ended June 30, 2018 and year ended December 31, 2017 are as follows:

	June 30, 2018					December 31, 2017
	Options Outstanding			Weighted Average Exercise Price		Options Outstanding			Weighted Average Exercise Price
Balance at beginning of period	1,548,719			$	101.48	1,737,213			$	98.44
Granted	6,000			97.91		174,000			105.66
Exercised	(58,734		)	89.62		(292,193		)	81.07
Lapsed or canceled	(56,033		)	114.70		(70,301		)	121.68
Balance at end of period	1,439,952			$	101.43	1,548,719			$	101.48
Options exercisable at end of period	1,067,969			$	98.93	800,902			$	94.33
Total fair value of options granted during the period	$	84,068				$	3,816,652

Summary of restricted stock and charges during the period

A summary of the Company's restricted stock as of June 30, 2018 and December 31, 2017 and charges during the six months ended June 30, 2018 and the year ended December 31, 2017, are as follows:

	June 30, 2018			December 31, 2017
Balance at beginning of period	3,298,216			3,202,031
Granted	1,700			96,185
Canceled	(8,300		)	—
Balance at end of period	3,291,616			3,298,216
Vested during the period	92,114			95,736
Compensation expense recorded	$	6,251,350		$	9,809,749
Total fair value of restricted stock granted during the period	$	163,831		$	9,905,986