Share-Based Compensation Stock Option Activity (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Exercises in Period, Total Intrinsic Value	$ 1,000	$ 300	$ 300
Stock Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options	4,500	24,500		32,500	46,250
Weighted Average Exercise Price, Options	$ 32.27	$ 29.11		$ 29.56	$ 30.77
Grants in Period, Net of Forfeitures	0	0	0
Weighted Average Exercise Price, Grants	$ 0	$ 0	$ 0
Exercises in Period	20,000	8,000	12,250
Weighted Average Exercise Price, Exercises	$ 28.39	$ 30.96	$ 33.40
Forfeitures and Expirations in Period, Options	0	0	1,500
Weighted Average Exercise Price, Forfeitures	$ 0.00	$ 0.00	$ 35.44
Exercisable Options	4,500
Options, Exercisable, Weighted Average Exercise Price	$ 32.27
Options, Exercisable, Weighted Average Remaining Contractual Term	2 years 10 months 24 days
Options, Exercisable, Intrinsic Value	$ 200	$ 1,000		$ 1,000
Employee Stock Option [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options	0
2004 non-employee plan [Member] | Stock Compensation Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding options	4,500
Award Vesting Period	3 years
Option maximum contractual term	10 years
Exercises in Period	14,199