Fair Value - Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands	Mar. 31, 2019	Dec. 31, 2018
Securities Available For Sale:
Total Securities Available For Sale	$ 500,608	$ 516,863
Fair Value Measurement on Recurring Basis
Securities Available For Sale:
Total Securities Available For Sale	500,608	516,863
Interest Rate swaps	906	485
Trading Securities:
Total Trading Securities	8,642	7,786
Liabilities:
Interest rate swaps	(1,227)	(686)
Fair Value Measurement on Recurring Basis | Quoted Prices in Active Markets for Identical Assets
Securities Available For Sale:
Total Securities Available For Sale	947	934
Interest Rate swaps	0	0
Trading Securities:
Total Trading Securities	8,591	7,735
Liabilities:
Interest rate swaps	0	0
Fair Value Measurement on Recurring Basis | Significant Other Observable Inputs
Securities Available For Sale:
Total Securities Available For Sale	499,661	515,929
Interest Rate swaps	906	485
Trading Securities:
Total Trading Securities	51	51
Liabilities:
Interest rate swaps	(1,227)	(686)
Fair Value Measurement on Recurring Basis | Significant Unobservable Inputs
Securities Available For Sale:
Total Securities Available For Sale	0	0
Interest Rate swaps	0	0
Trading Securities:
Total Trading Securities	0	0
Liabilities:
Interest rate swaps	0	0
U.S. Government sponsored entities
Securities Available For Sale:
Total Securities Available For Sale	130,375	132,694
U.S. Government sponsored entities | Fair Value Measurement on Recurring Basis
Securities Available For Sale:
Total Securities Available For Sale	130,375	132,694
Trading Securities:
Total Trading Securities	51	51
U.S. Government sponsored entities | Fair Value Measurement on Recurring Basis | Quoted Prices in Active Markets for Identical Assets
Securities Available For Sale:
Total Securities Available For Sale	0	0
Trading Securities:
Total Trading Securities	0	0
U.S. Government sponsored entities | Fair Value Measurement on Recurring Basis | Significant Other Observable Inputs
Securities Available For Sale:
Total Securities Available For Sale	130,375	132,694
Trading Securities:
Total Trading Securities	51	51
U.S. Government sponsored entities | Fair Value Measurement on Recurring Basis | Significant Unobservable Inputs
Securities Available For Sale:
Total Securities Available For Sale	0	0
Trading Securities:
Total Trading Securities	0	0
State & political subdivisions
Securities Available For Sale:
Total Securities Available For Sale	121,090	136,031
State & political subdivisions | Fair Value Measurement on Recurring Basis
Securities Available For Sale:
Total Securities Available For Sale	121,090	136,031
State & political subdivisions | Fair Value Measurement on Recurring Basis | Quoted Prices in Active Markets for Identical Assets
Securities Available For Sale:
Total Securities Available For Sale	0	0
State & political subdivisions | Fair Value Measurement on Recurring Basis | Significant Other Observable Inputs
Securities Available For Sale:
Total Securities Available For Sale	121,090	136,031
State & political subdivisions | Fair Value Measurement on Recurring Basis | Significant Unobservable Inputs
Securities Available For Sale:
Total Securities Available For Sale	0	0
Residential and multi-family mortgage
Securities Available For Sale:
Total Securities Available For Sale	207,491	206,053
Residential and multi-family mortgage | Fair Value Measurement on Recurring Basis
Securities Available For Sale:
Total Securities Available For Sale	207,491	206,053
Residential and multi-family mortgage | Fair Value Measurement on Recurring Basis | Quoted Prices in Active Markets for Identical Assets
Securities Available For Sale:
Total Securities Available For Sale	0	0
Residential and multi-family mortgage | Fair Value Measurement on Recurring Basis | Significant Other Observable Inputs
Securities Available For Sale:
Total Securities Available For Sale	207,491	206,053
Residential and multi-family mortgage | Fair Value Measurement on Recurring Basis | Significant Unobservable Inputs
Securities Available For Sale:
Total Securities Available For Sale	0	0
Corporate notes and bonds | Fair Value Measurement on Recurring Basis
Securities Available For Sale:
Total Securities Available For Sale	11,904	11,777
Corporate notes and bonds | Fair Value Measurement on Recurring Basis | Quoted Prices in Active Markets for Identical Assets
Securities Available For Sale:
Total Securities Available For Sale	0	0
Corporate notes and bonds | Fair Value Measurement on Recurring Basis | Significant Other Observable Inputs
Securities Available For Sale:
Total Securities Available For Sale	11,904	11,777
Corporate notes and bonds | Fair Value Measurement on Recurring Basis | Significant Unobservable Inputs
Securities Available For Sale:
Total Securities Available For Sale	0	0
Pooled SBA
Securities Available For Sale:
Total Securities Available For Sale	28,801	29,374
Pooled SBA | Fair Value Measurement on Recurring Basis
Securities Available For Sale:
Total Securities Available For Sale	28,801	29,374
Pooled SBA | Fair Value Measurement on Recurring Basis | Quoted Prices in Active Markets for Identical Assets
Securities Available For Sale:
Total Securities Available For Sale	0	0
Pooled SBA | Fair Value Measurement on Recurring Basis | Significant Other Observable Inputs
Securities Available For Sale:
Total Securities Available For Sale	28,801	29,374
Pooled SBA | Fair Value Measurement on Recurring Basis | Significant Unobservable Inputs
Securities Available For Sale:
Total Securities Available For Sale	0	0
Other | Fair Value Measurement on Recurring Basis
Securities Available For Sale:
Total Securities Available For Sale	947	934
Other | Fair Value Measurement on Recurring Basis | Quoted Prices in Active Markets for Identical Assets
Securities Available For Sale:
Total Securities Available For Sale	947	934
Other | Fair Value Measurement on Recurring Basis | Significant Other Observable Inputs
Securities Available For Sale:
Total Securities Available For Sale	0	0
Other | Fair Value Measurement on Recurring Basis | Significant Unobservable Inputs
Securities Available For Sale:
Total Securities Available For Sale	0	0
Corporate equity securities | Fair Value Measurement on Recurring Basis
Trading Securities:
Total Trading Securities	6,947	5,828
Corporate equity securities | Fair Value Measurement on Recurring Basis | Quoted Prices in Active Markets for Identical Assets
Trading Securities:
Total Trading Securities	6,947	5,828
Corporate equity securities | Fair Value Measurement on Recurring Basis | Significant Other Observable Inputs
Trading Securities:
Total Trading Securities	0	0
Corporate equity securities | Fair Value Measurement on Recurring Basis | Significant Unobservable Inputs
Trading Securities:
Total Trading Securities	0	0
Mutual funds | Fair Value Measurement on Recurring Basis
Trading Securities:
Total Trading Securities	871	1,058
Mutual funds | Fair Value Measurement on Recurring Basis | Quoted Prices in Active Markets for Identical Assets
Trading Securities:
Total Trading Securities	871	1,058
Mutual funds | Fair Value Measurement on Recurring Basis | Significant Other Observable Inputs
Trading Securities:
Total Trading Securities	0	0
Mutual funds | Fair Value Measurement on Recurring Basis | Significant Unobservable Inputs
Trading Securities:
Total Trading Securities	0	0
Certificates of deposit | Fair Value Measurement on Recurring Basis
Trading Securities:
Total Trading Securities	179	268
Certificates of deposit | Fair Value Measurement on Recurring Basis | Quoted Prices in Active Markets for Identical Assets
Trading Securities:
Total Trading Securities	179	268
Certificates of deposit | Fair Value Measurement on Recurring Basis | Significant Other Observable Inputs
Trading Securities:
Total Trading Securities	0	0
Certificates of deposit | Fair Value Measurement on Recurring Basis | Significant Unobservable Inputs
Trading Securities:
Total Trading Securities	0	0
Corporate notes & bonds
Securities Available For Sale:
Total Securities Available For Sale	11,904	11,777
Corporate notes & bonds | Fair Value Measurement on Recurring Basis
Trading Securities:
Total Trading Securities	594	581
Corporate notes & bonds | Fair Value Measurement on Recurring Basis | Quoted Prices in Active Markets for Identical Assets
Trading Securities:
Total Trading Securities	594	581
Corporate notes & bonds | Fair Value Measurement on Recurring Basis | Significant Other Observable Inputs
Trading Securities:
Total Trading Securities	0	0
Corporate notes & bonds | Fair Value Measurement on Recurring Basis | Significant Unobservable Inputs
Trading Securities:
Total Trading Securities	$ 0	$ 0