Share-based Compensation (Tables)

6 Months Ended

Jun. 30, 2020

Share-based Compensation [Abstract]

Summary of Information Concerning Stock Options Outstanding Including the Related Transactions under the Stock Option Plans

				Weighted-
				average
		Weighted-		remaining	Aggregate
	Number	average		contractual	intrinsic
	of shares	exercise		term in	value
	(in thousands)	price		years	(in thousands)
Options outstanding as of December 31, 2019	13,172	$	21.94
Granted	10,653		19.65
Exercised	(681)		17.99
Forfeited and expired	(69)		20.41
Options outstanding as of June 30, 2020	23,075		21.00	7.12	$	128,954
Options expected to vest as of June 30, 2020	22,612		21.02	7.06		126,208
Options exercisable as of June 30, 2020	9,273		19.34	3.59		62,467

Valuation of Option Grants under Stock Option Plans

	Three months ended
	June 30,
	2020	2019
Expected volatility	32.9%	29.9%
Weighted-average volatility	32.9%	29.9%
Expected dividends	4.48%	2.36%
Risk-free rate	0.5%	2.4%
Average risk-free rate	0.5%	2.4%
Expected term (in years)	7.4	7.4
Pre-vesting executive departure rate	0.6%	0.6%
Pre-vesting non-executive departure rate	2.5%

(1)Stock options were granted during the three months ended June 30, 2020 and 2019. There were no stock options granted during the three months ended March 31, 2020 and 2019.

Summary of the Status of Non-vested Time-based Restricted Stock and Restricted Stock Units

		Weighted
	Number	average
	of shares	grant-date
	(in thousands)	fair value
Non-vested shares and share units at December 31, 2019	5,189	$	27.58
Granted	9,104		20.54
Vested	(1,025)		27.58
Forfeited	(93)		27.57
Non-vested shares and share units at June 30, 2020	13,175	$	22.72