Stock-based Compensation (Narrative) (Details) - USD ($) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares authorized for issuance	1,500,000
Share-Based Compensation	$ 1,959	$ 2,059	$ 2,041
Restricted Stock [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Shares granted	36,196	42,786	22,629
Shares granted, weighted average grant date market value		$ 51.04	$ 58.89
Vesting period	3 years	3 years
Amortization of restricted stock bonus	$ 1,712	$ 1,514	$ 1,250
Total unrecognized compensation expense	$ 1,688
Total unrecognized compensation expense, weighted average period	29 days
Total fair value of shares vested	$ 1,500	1,089	$ 1,066
SARs [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total unrecognized compensation expense	$ 18	$ 265
Total unrecognized compensation expense, weighted average period	6 months	6 months
Total intrinsic value of options exercised	$ 2,162	$ 1,268
Average remaining contractual term	5 years 2 months 19 days	5 years 11 months 27 days
Outstanding, Aggregate Intrinsic Value	$ 8,395	$ 4,577
Share-Based Compensation	$ 247