Share-Based Compensation Arrangements (Compensation Cost for Share-based Compensation Arrangements) (Details) - USD ($) $ in Thousands		12 Months Ended
		Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Share-based Payment Arrangement [Abstract]
Share-based compensation expense		$ 3,766	$ 3,124	$ 2,602
Related income tax benefits	[1]	801	982	1,108
Excess Tax Expense (Benefit) from Stock Option Exercises and Issuance of Other Compensation-related Equity Instruments		$ (103)	$ 248	$ 496

[1] Includes $103 thousand of excess tax expenses recognized upon the settlement of share-based compensation awards in 2020. Includes $248 thousand and $496 thousand, respectively, of excess tax benefits recognized upon the settlement of share-based compensation awards in 2019 and 2018.