Shareholders' Equity (Regulatory Captial Requirements) (Details) $ in Thousands		Mar. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)
Corporation [Member]
Total Capital (to Risk-Weighted Assets):
Total Capital		$ 549,669	$ 539,496
Total Capital to Risk-Weighted Assets		0.1385	0.1351
Total Capital for Capital Adequacy Purposes		$ 317,554	$ 319,532
Total Capital for Capital Adequacy Purposes to Risk-Weighted Assets		0.0800	0.0800
Tier 1 Capital (to Risk-Weighted Assets):
Tier 1 Capital		$ 515,478	$ 503,791
Tier 1 Capital to Risk Weighted-Assets		0.1299	0.1261
Tier 1 Capital Required For Capital Adequacy Purposes		$ 238,165	$ 239,649
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		$ 493,479	$ 481,792
Common Equity Tier 1 Capital to Risk-Weighted Assets		0.1243	0.1206
Common Equity Tier 1 Capital Required for Capital Adequacy		$ 178,624	$ 179,737
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]	$ 515,478	$ 503,791
Tier 1 Leverage Capital to Average Assets	[1]	0.0911	0.0895
Tier 1 Leverage Capital Required for Capital Adequacy Purposes	[1]	$ 226,336	$ 225,209
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		$ 544,695	$ 534,288
Total Capital to Risk-Weighted Assets		0.1372	0.1338
Total Capital for Capital Adequacy Purposes		$ 317,526	$ 319,503
Total Capital for Capital Adequacy Purposes to Risk-Weighted Assets		0.0800	0.0800
Total Capital To Be Well Capitalized		$ 396,907	$ 399,379
Total Capital To Be Well Capitalized to Risk Weighted-Assets		0.1000	0.1000
Tier 1 Capital (to Risk-Weighted Assets):
Tier 1 Capital		$ 510,504	$ 498,583
Tier 1 Capital to Risk Weighted-Assets		0.1286	0.1248
Tier 1 Capital Required For Capital Adequacy Purposes		$ 238,144	$ 239,627
Tier 1 Capital Required for Capital Adequacy Purposes to Risk Weighted-Assets		0.0600	0.0600
Tier 1 Capital Required To Be Well Capitalized		$ 317,526	$ 319,503
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		$ 510,504	$ 498,583
Common Equity Tier 1 Capital to Risk-Weighted Assets		0.1286	0.1248
Common Equity Tier 1 Capital Required for Capital Adequacy		$ 178,608	$ 179,721
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		$ 257,990	$ 259,596
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]	$ 510,504	$ 498,583
Tier 1 Leverage Capital to Average Assets	[1]	0.0903	0.0886
Tier 1 Leverage Capital Required for Capital Adequacy Purposes	[1]	$ 226,255	$ 225,126
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]	$ 282,819	$ 281,407
Tier 1 Leverage Capital Required To Be Well Capitalized to Average Assets	[1]	0.0500	0.0500

[1] Leverage ratio.