Share-based compensation (Notes)

12 Months Ended

Dec. 31, 2019

Share-based Payment Arrangement [Abstract]

Stock plan

For the purpose of attracting and retaining the highest-quality personnel, providing for additional incentives, and promoting the success of our Company, we have historically issued two forms of share-based compensation under our equity incentive plan: (i) options to purchase common stock and (ii) restricted stock. We have not granted any options since 2002. Each restricted share issued reduced the share reserve by three shares (3:1 ratio) prior to March 23, 2018, and by one share (1:1 ratio) on and after March 23, 2018. As of December 31, 2019, there were 1,858,673 shares reserved for the granting of future options and stock awards under the equity incentive plan.

In addition, the stock plan permits us to issue share awards to our employees, non-employees, and non-employee directors. A share award is an award of common stock that (i) may be fully vested upon issuance or (ii) may be subject to the risk of forfeiture under Section 83 of the Internal Revenue Code. Shares issued generally vest over a four-year period from the date of issuance, and the sale of the shares is restricted prior to the date of vesting. The unearned portion of time-based awards is amortized as stock compensation expense on a straight-line basis over the vesting period. Certain restricted share awards are subject to vesting based upon the satisfaction of levels of performance and market conditions. Failure to satisfy the threshold performance conditions will result in the forfeiture of shares. Forfeiture of share awards with time-based or performance-based restrictions results in a reversal of previously recognized share-based compensation expense. Forfeiture of share awards with market-based restrictions does not result in a reversal of previously recognized share-based compensation expense.

The following is a summary of the stock awards activity under our equity incentive plan and related information for the years ended December 31, 2019, 2018, and 2017:



			Number of Share Awards			Weighted-Average Grant Date Fair Value Per Share
Outstanding at December 31, 2016			1,135,788			$		87.21
Granted			688,295			$		108.22
Vested			(423,705		)	$		85.16
Forfeited			(5,796		)	$		101.45
Outstanding at December 31, 2017			1,394,582			$		95.79
Granted			741,244			$		121.20
Vested			(403,120		)	$		103.83
Forfeited			(20,330		)	$		106.38
Outstanding at December 31, 2018			1,712,376			$		105.22
Granted			768,625			$		134.70
Vested			(666,836		)	$		96.77
Forfeited			(14,480		)	$		119.88
Outstanding at December 31, 2019			1,799,685			$		119.59

	Year Ended December 31,
(In thousands)	2019		2018			2017
Total grant date fair value of stock awards vested	$	64,530	$	41,854		$	36,083
Total gross compensation recognized for stock awards	$	68,036	$	57,341		$	42,292
Capitalized stock compensation	$	24,396	$	22,322		$	16,682

Certain restricted stock awards granted during 2016 through 2019 are subject to performance and market conditions. The grant date fair value of these awards is determined using a Monte Carlo simulation pricing model using the following assumptions for 2019 and 2018, respectively: (i) expected term of 3.0 years and 3.0 years (equal to the remaining performance measurement period at the grant date), (ii) volatility of 18.0% and 16.0% (approximating a blended average of implied and historical volatilities), (iii) dividend yield of 3.2% and 3.1%, and (iv) risk-free rate of 2.60% and 2.15%.

As of December 31, 2019, there was $168.5 million of unrecognized compensation related to unvested share awards under the equity incentive plan, which is expected to be recognized over the next four years and has a weighted-average vesting period of approximately 19 months.