Shareholders' Equity (Regulatory Captial Requirements) (Details) - USD ($) $ in Thousands		Jun. 30, 2015	Dec. 31, 2014
Corporation [Member]
Total Capital (to Risk-Weighted Assets):
Total Capital		$ 358,896	$ 343,934
Total Capital to Risk-Weighted Assets		12.78%	12.56%
Total Capital for Capital Adequacy Purposes		$ 224,669	$ 219,149
Total Capital for Capital Adequacy Purposes to Risk-Weighted Assets		8.00%	8.00%
Tier 1 Capital (to Risk-Weighted Assets):
Tier 1 Capital		$ 330,973	$ 315,575
Tier 1 Capital to Risk Weighted-Assets		11.79%	11.52%
Tier 1 Capital Required For Capital Adequacy Purposes		$ 168,502	$ 109,574
Tier 1 Capital Required for Capital Adequacy Purposes to Risk Weighted-Assets		6.00%	4.00%
Tier 1 Capital (to Average Assets):
Tier 1 Leverage Capital	[1]	$ 330,973	$ 315,575
Tier 1 Leverage Capital to Average Assets	[1]	9.31%	9.14%
Tier 1 Leverage Capital Required for Capital Adequacy Purposes	[1]	$ 142,262	$ 138,090
Tier 1 Leverage Capital Required for Capital Adequacy Purposes to Average Assets	[1]	4.00%	4.00%
Common Equity Tier 1 Capital [Abstract]
Common Equity Tier 1 Capital	[2]	$ 308,974
Common Equity Tier 1 Capital to Risk Weighted Assets	[2]	11.00%
Common Equity Tier 1 Capital Required for Capital Adequacy	[2]	$ 126,376
Common Equity Tier 1 Capital for Capital Adequacy to Risk Weighted Assets	[2]	4.50%
Bank [Member]
Total Capital (to Risk-Weighted Assets):
Total Capital		$ 354,710	$ 339,268
Total Capital to Risk-Weighted Assets		12.63%	12.39%
Total Capital for Capital Adequacy Purposes		$ 224,613	$ 219,075
Total Capital for Capital Adequacy Purposes to Risk-Weighted Assets		8.00%	8.00%
Total Capital To Be Well Capitalized		$ 280,766	$ 273,844
Total Capital To Be Well Capitalized to Risk Weighted-Assets		10.00%	10.00%
Tier 1 Capital (to Risk-Weighted Assets):
Tier 1 Capital		$ 326,787	$ 310,909
Tier 1 Capital to Risk Weighted-Assets		11.64%	11.35%
Tier 1 Capital Required For Capital Adequacy Purposes		$ 168,460	$ 109,537
Tier 1 Capital Required for Capital Adequacy Purposes to Risk Weighted-Assets		6.00%	4.00%
Tier 1 Capital Required To Be Well Capitalized		$ 224,613	$ 164,306
Tier 1 Capital Required To Be Well Capitalized to Risk Weighted-Assets		8.00%	6.00%
Tier 1 Capital (to Average Assets):
Tier 1 Leverage Capital	[1]	$ 326,787	$ 310,909
Tier 1 Leverage Capital to Average Assets	[1]	9.20%	9.01%
Tier 1 Leverage Capital Required for Capital Adequacy Purposes	[1]	$ 142,145	$ 137,964
Tier 1 Leverage Capital Required for Capital Adequacy Purposes to Average Assets	[1]	4.00%	4.00%
Tier 1 Leverage Capital Required To Be Well Capitalized	[1]	$ 177,681	$ 172,454
Tier 1 Leverage Capital Required To Be Well Capitalized to Average Assets	[1]	5.00%	5.00%
Common Equity Tier 1 Capital [Abstract]
Common Equity Tier 1 Capital	[2]	$ 326,787
Common Equity Tier 1 Capital to Risk Weighted Assets	[2]	11.64%
Common Equity Tier 1 Capital Required for Capital Adequacy	[2]	$ 126,345
Common Equity Tier 1 Capital for Capital Adequacy to Risk Weighted Assets	[2]	4.50%
Common Equity Tier 1 Capital Required to be Well Capitalized	[2]	$ 182,498
Common Equity Tier 1 Capital Required to be Well Capitalized to Risk Weighted Assets	[2]	6.50%

[1] Leverage ratio.

[2] (1)New capital ratio effective January 1, 2015 under the Basel III capital requirements. See additional discussion of Basel III and the new regulatory capital requirements in the “Supervision and Regulation” section in the Annual Report on Form 10-K for the fiscal year ended December 31, 2014.