Shareholders' Equity (Regulatory Captial Requirements) (Details) (USD $) In Thousands, unless otherwise specified	Mar. 31, 2015		Dec. 31, 2014
Corporation [Member]
Total Capital (to Risk-Weighted Assets):
Total Capital	$ 352,521		$ 343,934
Total Capital to Risk-Weighted Assets	12.80%		12.56%
Total Capital for Capital Adequacy Purposes	220,262		219,149
Total Capital for Capital Adequacy Purposes to Risk-Weighted Assets	8.00%		8.00%
Total Capital To Be Well Capitalized			273,936
Tier 1 Capital (to Risk-Weighted Assets):
Tier 1 Capital	324,375		315,575
Tier 1 Capital to Risk Weighted-Assets	11.78%		11.52%
Tier 1 Capital Required For Capital Adequacy Purposes	165,196		109,574
Tier 1 Capital Required for Capital Adequacy Purposes to Risk Weighted-Assets	6.00%		4.00%
Tier 1 Capital Required To Be Well Capitalized			164,361
Tier 1 Capital (to Average Assets):
Tier 1 Leverage Capital	324,375	[1]	315,575	[1]
Tier 1 Leverage Capital to Average Assets	9.21%	[1]	9.14%	[1]
Tier 1 Leverage Capital Required for Capital Adequacy Purposes	140,864	[1]	138,090	[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			172,612	[1]
Common Equity Tier 1 Capital [Abstract]
Common Equity Tier 1 Capital	302,376	[2]
Common Equity Tier 1 Capital to Risk Weighted Assets	10.98%	[2]
Common Equity Tier 1 Capital Required for Capital Adequacy	123,897	[2]
Common Equity Tier 1 Capital for Capital Adequacy to Risk Weighted Assets	4.50%	[2]
Bank [Member]
Total Capital (to Risk-Weighted Assets):
Total Capital	347,674		339,268
Total Capital to Risk-Weighted Assets	12.63%		12.39%
Total Capital for Capital Adequacy Purposes	220,187		219,075
Total Capital for Capital Adequacy Purposes to Risk-Weighted Assets	8.00%		8.00%
Total Capital To Be Well Capitalized	275,234		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	319,528		310,909
Tier 1 Capital to Risk Weighted-Assets	11.61%		11.35%
Tier 1 Capital Required For Capital Adequacy Purposes	165,140		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	220,187		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	319,528	[1]	310,909	[1]
Tier 1 Leverage Capital to Average Assets	9.08%	[1]	9.01%	[1]
Tier 1 Leverage Capital Required for Capital Adequacy Purposes	140,738	[1]	137,964	[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	175,922	[1]	172,454	[1]
Tier 1 Leverage Capital Required To Be Well Capitalized to Average Assets	5.00%	[1]	5.00%	[1]
Common Equity Tier 1 Capital [Abstract]
Common Equity Tier 1 Capital	319,528	[2]
Common Equity Tier 1 Capital to Risk Weighted Assets	11.61%	[2]
Common Equity Tier 1 Capital Required for Capital Adequacy	123,855	[2]
Common Equity Tier 1 Capital for Capital Adequacy to Risk Weighted Assets	4.50%	[2]
Common Equity Tier 1 Capital Required to be Well Capitalized	$ 178,902	[2]
Common Equity Tier 1 Capital Required to be Well Capitalized to Risk Weighted Assets	6.50%	[2]

[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.