Stock-Based Compensation (Tables)

6 Months Ended

Jun. 30, 2020

Deferred Compensation Arrangements [Abstract]

Share-based Payment Arrangement, Expensed and Capitalized, Amount

The following is a summary of stock-based compensation expense, net of forfeitures, included in General and administrative expenses in the Condensed Consolidated Statements of Income ($ in thousands):

	Three Months Ended				Six Months Ended
	June 30,				June 30,
	2020		2019		2020		2019
Non-cash stock-based compensation expense	$	470	$	477	$	2,315	$	2,478

Schedule of Share-based Payment Award, Stock Options, Valuation Assumptions [Table Text Block]

The fair value of each grant is estimated on the date of grant using the Black-Scholes option-pricing model with the following weighted average assumptions:

	2020	2019
Dividend yield	5.1%	5.5%
Expected volatility	17.1%	18.6%
Expected lives	2.9 years	2.9 years
Risk-free interest rate	1.30%	2.50%

Schedule of Stock Option Activity

The following table summarizes our outstanding stock options:

			Weighted Average
	Number	Weighted Average	Remaining
	of Shares	Exercise Price	Contractual Life (Years)
Options outstanding January 1, 2019	920,346	$69.24
Options granted	602,000	$79.96
Options exercised	(367,830)	$71.14
Options outstanding, June 30, 2019	1,154,516	$74.26
Exercisable at June 30, 2019	663,997	$73.64
Options outstanding January 1, 2020	1,004,014	$74.35
Options granted	592,000	$90.32
Options exercised	(512,509)	$72.98
Options forfeited	(10,500)	$88.73
Options outstanding, June 30, 2020	1,073,005	$83.68	3.95
Exercisable at June 30, 2020	601,994	$81.09	3.65