Share-Based Compensation and Benefit Plans (Other Share-Based Compensation Activity) (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Employee stock purchase plan [Member]
Share-Based Compensation and Benefit Plans
Compensation expense for share-based compensation	$ 717	$ 622	$ 2,060	$ 1,831
Income tax benefit from compensation expense for share-based compensation	180	155	517	456
Restricted stock [Member]
Share-Based Compensation and Benefit Plans
Compensation expense for share-based compensation	392	351	1,094	1,038
Income tax benefit from compensation expense for share-based compensation	$ 99	$ 87	$ 275	$ 258