Share-Based Compensation Arrangements (Share Options Activity) (Details) - Stock Options [Member] - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Number of Share Options:
Beginning of period	309,116
Granted	53,400	48,600	25,850
Exercised	(143,237)
Forfeited or expired	0
End of period	219,279	309,116
Options exercisable	89,954
Options expected to vest in future periods	129,325
Weighted Average Exercise Price (in dollars per share):
Beginning of period	$ 26.84
Granted	40.25
Exercised	22.87
Forfeited or expired	0.00
End of period	32.70	$ 26.84
Options exercisable	25.34
Options expected to vest in future periods	$ 37.82
Outstanding Weighted Average Remaining Contractual Term	7 years 2 months
Exercisable Weighted Average Remaining Contractual Term	4 years 9 months 7 days
Expected to Vest Weighted Average Remaining Contractual Term	8 years 10 months 5 days
Outstanding Aggregate Intrinsic Value	$ 5,121
Exercisable Aggregate Intrinsic Value	2,763
Expected to Vest Aggregate Intrinsic Value	$ 2,358