Shareholders' Equity (Regulatory Captial Requirements) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Corporation [Member]
Total Capital (to Risk-Weighted Assets):
Total Capital	$ 304,716		$ 279,751
Total Capital to Risk-Weighted Assets	13.26%		12.86%
Total Capital for Capital Adequacy Purposes	183,876		174,073
Total Capital for Capital Adequacy Purposes to Risk-Weighted Assets	8.00%		8.00%
Total Capital To Be Well Capitalized	229,845		217,592
Total Capital To Be Well Capitalized to Risk Weighted-Assets	10.00%		10.00%
Tier 1 Capital (to Risk-Weighted Assets):
Tier 1 Capital	275,956		252,516
Tier 1 Capital to Risk Weighted-Assets	12.01%		11.61%
Tier 1 Capital Required For Capital Adequacy Purposes	91,938		87,037
Tier 1 Capital Required for Capital Adequacy Purposes to Risk Weighted-Assets	4.00%		4.00%
Tier 1 Capital Required To Be Well Capitalized	137,907		130,555
Tier 1 Capital Required To Be Well Capitalized to Risk Weighted-Assets	6.00%		6.00%
Tier 1 Capital (to Average Assets):
Tier 1 Leverage Capital	275,956	[1]	252,516	[1]
Tier 1 Leverage Capital to Average Assets	9.30%	[1]	8.70%	[1]
Tier 1 Leverage Capital Required for Capital Adequacy Purposes	118,733	[1]	116,158	[1]
Tier 1 Leverage Capital Required for Capital Adequacy Purposes to Average Assets	4.00%	[1]	4.00%	[1]
Tier 1 Leverage Capital Required To Be Well Capitalized	148,417	[1]	145,198	[1]
Tier 1 Leverage Capital Required To Be Well Capitalized to Average Assets	5.00%	[1]	5.00%	[1]
Bank [Member]
Total Capital (to Risk-Weighted Assets):
Total Capital	299,503		275,183
Total Capital to Risk-Weighted Assets	13.05%		12.66%
Total Capital for Capital Adequacy Purposes	183,651		173,845
Total Capital for Capital Adequacy Purposes to Risk-Weighted Assets	8.00%		8.00%
Total Capital To Be Well Capitalized	229,564		217,307
Total Capital To Be Well Capitalized to Risk Weighted-Assets	10.00%		10.00%
Tier 1 Capital (to Risk-Weighted Assets):
Tier 1 Capital	270,778		247,983
Tier 1 Capital to Risk Weighted-Assets	11.80%		11.41%
Tier 1 Capital Required For Capital Adequacy Purposes	91,826		86,923
Tier 1 Capital Required for Capital Adequacy Purposes to Risk Weighted-Assets	4.00%		4.00%
Tier 1 Capital Required To Be Well Capitalized	137,738		130,384
Tier 1 Capital Required To Be Well Capitalized to Risk Weighted-Assets	6.00%		6.00%
Tier 1 Capital (to Average Assets):
Tier 1 Leverage Capital	270,778	[1]	247,983	[1]
Tier 1 Leverage Capital to Average Assets	9.14%	[1]	8.55%	[1]
Tier 1 Leverage Capital Required for Capital Adequacy Purposes	118,535	[1]	115,961	[1]
Tier 1 Leverage Capital Required for Capital Adequacy Purposes to Average Assets	4.00%	[1]	4.00%	[1]
Tier 1 Leverage Capital Required To Be Well Capitalized	$ 148,169	[1]	$ 144,952	[1]
Tier 1 Leverage Capital Required To Be Well Capitalized to Average Assets	5.00%	[1]	5.00%	[1]

[1] Leverage ratio