Shareholders' Equity (Regulatory Captial Requirements) (Details) $ in Thousands		Sep. 30, 2023 USD ($)	Dec. 31, 2022 USD ($)
Corporation [Member]
Total Capital (to Risk-Weighted Assets):
Total Capital		$ 606,512	$ 605,005
Total Capital to Risk-Weighted Assets		0.1148	0.1237
Total Capital for Capital Adequacy Purposes		$ 422,709	$ 391,363
Total Capital for Capital Adequacy Purposes to Risk-Weighted Assets		0.0800	0.0800
Tier 1 Capital (to Risk-Weighted Assets):
Tier 1 Capital		$ 569,046	$ 571,794
Tier 1 Capital to Risk Weighted-Assets		0.1077	0.1169
Tier 1 Capital Required For Capital Adequacy Purposes		$ 317,032	$ 293,522
Tier 1 Capital Required for Capital Adequacy Purposes to Risk Weighted-Assets		0.0600	0.0600
Common Equity Tier 1 Capital [Abstract]
Common Equity Tier 1 Capital		$ 547,050	$ 549,798
Common Equity Tier 1 Capital to Risk-Weighted Assets		0.1035	0.1124
Common Equity Tier 1 Capital Required for Capital Adequacy		$ 237,774	$ 220,142
Common Equity Tier 1 Capital for Capital Adequacy Purposes to Risk-Weighted Assets		0.0450	0.0450
Tier 1 Capital (to Average Assets):
Tier 1 Leverage Capital	[1]	$ 569,046	$ 571,794
Tier 1 Leverage Capital to Average Assets	[1]	0.0787	0.0865
Tier 1 Leverage Capital Required for Capital Adequacy Purposes	[1]	$ 289,211	$ 264,295
Tier 1 Leverage Capital Required for Capital Adequacy Purposes to Average Assets	[1]	0.0400	0.0400
Bank [Member]
Total Capital (to Risk-Weighted Assets):
Total Capital		$ 600,123	$ 588,090
Total Capital to Risk-Weighted Assets		0.1136	0.1202
Total Capital for Capital Adequacy Purposes		$ 422,574	$ 391,260
Total Capital for Capital Adequacy Purposes to Risk-Weighted Assets		0.0800	0.0800
Total Capital To Be Well Capitalized		$ 528,217	$ 489,074
Total Capital To Be Well Capitalized to Risk Weighted-Assets		0.1000	0.1000
Tier 1 Capital (to Risk-Weighted Assets):
Tier 1 Capital		$ 562,657	$ 554,879
Tier 1 Capital to Risk Weighted-Assets		0.1065	0.1135
Tier 1 Capital Required For Capital Adequacy Purposes		$ 316,930	$ 293,445
Tier 1 Capital Required for Capital Adequacy Purposes to Risk Weighted-Assets		0.0600	0.0600
Tier 1 Capital Required To Be Well Capitalized		$ 422,574	$ 391,260
Tier 1 Capital Required To Be Well Capitalized to Risk Weighted-Assets		0.0800	0.0800
Common Equity Tier 1 Capital [Abstract]
Common Equity Tier 1 Capital		$ 562,657	$ 554,879
Common Equity Tier 1 Capital to Risk-Weighted Assets		0.1065	0.1135
Common Equity Tier 1 Capital Required for Capital Adequacy		$ 237,698	$ 220,083
Common Equity Tier 1 Capital for Capital Adequacy Purposes to Risk-Weighted Assets		0.0450	0.0450
Common Equity Tier 1 Capital To Be Well Capitalized		$ 343,341	$ 317,898
Common Equity Tier 1 Capital To Be Well Capitalized to Risk-Weighted Assets		0.0650	0.0650
Tier 1 Capital (to Average Assets):
Tier 1 Leverage Capital	[1]	$ 562,657	$ 554,879
Tier 1 Leverage Capital to Average Assets	[1]	0.0778	0.0840
Tier 1 Leverage Capital Required for Capital Adequacy Purposes	[1]	$ 289,117	$ 264,177
Tier 1 Leverage Capital Required for Capital Adequacy Purposes to Average Assets	[1]	0.0400	0.0400
Tier 1 Leverage Capital Required To Be Well Capitalized	[1]	$ 361,397	$ 330,222
Tier 1 Leverage Capital Required To Be Well Capitalized to Average Assets	[1]	0.0500	0.0500

[1] Leverage ratio.