Securities - Unrealized Loss Positions (Details)	6 Months Ended
	Jun. 30, 2019 USD ($) security	Dec. 31, 2018 USD ($)
Fair value
Less Than 12 Months, Fair Value	$ 425,000	$ 28,423,000
12 Months or More, Fair Value	59,120,000	109,110,000
Total Fair Value	59,545,000	137,533,000
Unrealized Loss
Less Than 12 Months, Unrealized Loss	3,000	162,000
12 Months or More, Unrealized Loss	278,000	2,504,000
Total Unrealized Loss	$ 281,000	2,666,000
Other information
Number of positions considered temporarily impaired | security	102
Debt securities considered temporarily impaired	$ 59,545,000	137,533,000
Other than temporary impairment	0
U.S. government agencies and corporations
Fair value
Less Than 12 Months, Fair Value		997,000
12 Months or More, Fair Value	15,693,000	15,725,000
Total Fair Value	15,693,000	16,722,000
Unrealized Loss
Less Than 12 Months, Unrealized Loss		1,000
12 Months or More, Unrealized Loss	68,000	535,000
Total Unrealized Loss	68,000	536,000
Other information
Debt securities considered temporarily impaired	15,693,000	16,722,000
Mortgage-backed securities
Fair value
Less Than 12 Months, Fair Value	8,000	17,934,000
12 Months or More, Fair Value	32,742,000	72,830,000
Total Fair Value	32,750,000	90,764,000
Unrealized Loss
Less Than 12 Months, Unrealized Loss	1,000	132,000
12 Months or More, Unrealized Loss	182,000	1,757,000
Total Unrealized Loss	183,000	1,889,000
Other information
Debt securities considered temporarily impaired	32,750,000	90,764,000
Obligations of states and political subdivisions
Fair value
Less Than 12 Months, Fair Value	417,000	9,492,000
12 Months or More, Fair Value	10,685,000	20,555,000
Total Fair Value	11,102,000	30,047,000
Unrealized Loss
Less Than 12 Months, Unrealized Loss	2,000	29,000
12 Months or More, Unrealized Loss	28,000	212,000
Total Unrealized Loss	30,000	241,000
Other information
Debt securities considered temporarily impaired	$ 11,102,000	$ 30,047,000
Standard & Poor's, A Rating
Other information
Percentage of portfolio with rating	97.00%
Percentage of portfolio with rating in an unrealized loss positions	99.00%
Not A Rating Or Better
Other information
Percentage of portfolio with rating	1.00%