Share-Based Compensation Arrangements (Share Options Activity) (Details) - Stock Options [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Number of Share Options:
Beginning of period	222,615
Granted	61,800	47,950	47,725
Exercised	(35,600)
Forfeited or expired	0
End of period	248,815	222,615
Options exercisable	95,240
Options expected to vest in future periods	153,575
Weighted Average Exercise Price (in dollars per share):
Beginning of period	$ 42.92
Granted	48.65
Exercised	35.70
Forfeited or expired	0
End of period	45.38	$ 42.92
Options exercisable	33.57
Options expected to vest in future periods	$ 52.70
Outstanding Weighted Average Remaining Contractual Term	7 years 3 months 7 days
Exercisable Weighted Average Remaining Contractual Term	4 years 8 months 15 days
Expected to Vest Weighted Average Remaining Contractual Term	8 years 10 months 6 days
Outstanding Aggregate Intrinsic Value	$ 2,308
Exercisable Aggregate Intrinsic Value	1,926
Expected to Vest Aggregate Intrinsic Value	$ 382