Income Taxes, Effective Income Tax Rate Reconciliation (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Effective Income Tax Rate Reconciliation, Amount [Abstract]
Tax Provision at Federal Statutory Rate									$ 15,816	$ 12,543	$ 19,068
Interest on Obligations of States and Political Subdivisions exempt from Federal Taxation									(358)	(338)	(617)
State and Local Income Taxes, Net of Federal Income Tax Benefit									6,304	4,791	3,573
Bank Owned Life Insurance									(460)	(434)	(696)
Low-Income Housing Tax Credit									(2,078)	(1,624)	(1,546)
Out of Period Adjustment									0	(802)	0
Deferred Tax Asset Remeasurement									0	0	6,256
Other, Net									53	67	73
Total Provision for Taxes	$ 5,037	$ 4,660	$ 4,903	$ 4,677	$ 4,258	$ 2,995	$ 3,589	$ 3,361	$ 19,277	$ 14,203	$ 26,111
Effective Income Tax Rate Reconciliation, Percent [Abstract]
Tax Provision at Federal Statutory Rate									21.00%	21.00%	35.00%
Interest on Obligations of States and Political Subdivisions exempt from Federal Taxation									(0.50%)	(0.60%)	(1.10%)
State and Local Income Taxes, Net of Federal Income Tax Benefit									8.40%	7.90%	6.50%
Bank Owned Life Insurance									(0.60%)	(0.70%)	(1.30%)
Low-Income Housing Tax Credit									(2.80%)	(2.70%)	(2.80%)
Out of Period Adjustment									(0.00%)	(1.30%)	(0.00%)
Deferred Tax Asset Remeasurement									0.00%	0.00%	11.50%
Other, Net									0.10%	0.10%	0.10%
Total Provision for Taxes									25.60%	23.80%	47.90%