Incentive Plan (Tables)

12 Months Ended

Dec. 31, 2015

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

Schedule of Nonvested Performance-based Units Activity

Below is a summary of our long-term incentive unit activity for the year ended December 31, 2015.



Unvested Long-term Incentive Units	Units		Weighted-Average Grant Date Fair Value
Unvested, beginning of period	314,415		$	59.34
Granted	127,252		66.99
Vested	(143,898	)	59.65
Cancelled or expired	(16,878	)	58.13
Unvested, end of period	280,891		62.72

Schedule of Share-based Compensation, Performance Based Awards

The awards, which were determined to contain a market condition, utilize total shareholder return, or TSR, over a three-year measurement period as the market performance metric. Awards will vest based on the Company’s TSR relative to the MSCI US REIT Index, or RMS, over a three-year market performance period, or the Market Performance Period, commencing in January 2014 or January 2015, as applicable (or, if earlier, ending on the date on which a change in control of the Company occurs), subject to continued services. Vesting with respect to the market condition is measured based on the difference between the Company’s TSR percentage and the TSR percentage of the RMS, or the RMS Relative Market Performance. In the event that the RMS Relative Market Performance during the Market Performance Period is achieved at the “threshold,” “target” or “high” level as set forth below, the awards will become vested as to the market condition with respect to the percentage of Class D units or RSUs, as applicable, set forth below:



Level	RMS Relative Market Performance (2014 Awards)	RMS Relative Market Performance (2015 Awards)	Market Performance Vesting Percentage
Below Threshold Level	< 0 basis points	< -300 basis points	0	%
Threshold Level	0 basis points	-300 basis points	25	%
Target Level	325 basis points	100 basis points	50	%
High Level	> 650 basis points	> 500 basis points	100	%

Summary of Incentive Award Plan Stock Options

The following table summarizes the Amended and Restated 2004 Incentive Award Plan’s stock option activity for the year ended December 31, 2015:



	Year Ended December 31, 2015
	Shares		Weighted average exercise price
Options outstanding, beginning of period	80,933		$	37.25
Exercised	(29,311	)	30.58
Options outstanding, end of period	51,622		$	41.04
Exercisable, end of period	51,622		$	41.04

Summary of Stock Option Outstanding And Exercisable

The following table summarizes information about stock options outstanding and exercisable as of December 31, 2015:



Options outstanding and exercisable
Exercise price	Number outstanding	Weighted average remaining contractual life (years)	Weighted average exercise price		Aggregate intrinsic value
$33.18	4,175	0.84	$	33.18	$	177,187
$41.73	47,447	1.34	41.73		1,607,979
	51,622	1.30	$	41.04	$	1,785,166

Schedule of Restricted Stock Activity

Below is a summary of our restricted stock activity for the year ended December 31, 2015.



Unvested Restricted Stock	Shares		Weighted-Average Grant Date Fair Value
Unvested, beginning of period	302,298		$	57.10
Granted ⁽¹⁾	109,780		66.90
Vested	(99,988	)	59.57
Cancelled or expired	(41,376	)	56.85
Unvested, end of period	270,714		60.20


(1)	All restricted stock awards granted in 2015 are subject only to service conditions.