Long-Term Compensation (Tables)

12 Months Ended

Dec. 31, 2017

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Summary of Assumptions Used for Each Grant

The following table details the assumptions used for each grant based on the year it was granted (dollars in thousands):

	2017			2016			2015
Risk free interest rate		1.49	%		0.99	%		0.86	%
Expected volatility		22.2	%		20.5	%		28.0	%
Aggregate fair value	$	20,400		$	26,600		$	26,500

POP LTIP Units [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Stock Options, RSU and Performance Share Awards

The performance criteria were met for the 2015 – 2017 and 2014 – 2016 performance periods, which resulted in the pool being awarded in January 2018 and 2017, respectively, in the form of common stock and vested POP LTIP Units. See below for details on these performance periods (dollars and units in thousands):

	2015 – 2017		2014 – 2016
Performance pool	$	110,230	$	62,220
Common stock		582		486
Vested POP LTIP Units and LTIP Units		1,170		698
Grant date fair value	$	62.65	$	52.53

Restricted Stock Units (RSUs) [Member]

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Stock Options, RSU and Performance Share Awards

Each RSU represents the right to receive one share of common stock of the Parent. The following table summarizes the activity for RSUs for the year ended December 31, 2017 (units in thousands):

	Unvested RSUs			Weighted Average Grant Date Fair Value
Balance at January 1, 2017		1,492		$	40.62
Granted		759			50.76
Vested and distributed		(797	)		41.34
Forfeited		(80	)		44.68
Balance at December 31, 2017		1,374		$	45.57

Operating Partnership Long Term Incentive Plan Units

Share Based Compensation Arrangement By Share Based Payment Award [Line Items]

Stock Options, RSU and Performance Share Awards

The following table summarizes the activity for LTIP Units for the year ended December 31, 2017 (units in thousands):

	Vested LTIP Units			Unvested LTIP Units			Unvested Weighted Average Grant Date Fair Value
Balance at January 1, 2017		743			1,476		$	40.72
Granted		-			1,041			51.11
Vested LTIP Units		688			(688	)		41.13
Vested POP LTIP Units (1)		698			-		N/A
Conversion to common limited partnership units		(597	)		-		N/A
Balance at December 31, 2017		1,532			1,829		$	46.48