Employee Benefit Plans, Noncontributory Defined Benefit Pension Plan (Details) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	Sep. 30, 2018 USD ($) Plan	Sep. 30, 2017 USD ($)
Employee Benefit Plans [Abstract]
Number of plans | Plan			2
Pension Plan [Member]
Components of net periodic benefit cost [Abstract]
Net periodic benefit cost	$ 71	$ 37	$ (21)	$ 112
Employer contributions			0
Pension Plan [Member] | Salary and Employee Benefits [Member]
Components of net periodic benefit cost [Abstract]
Service cost	90	87	269	262
Pension Plan [Member] | Other Expenses [Member]
Components of net periodic benefit cost [Abstract]
Interest cost	164	168	489	503
Expected return on plan assets	(230)	(274)	(919)	(821)
Net amortization and deferral	$ 47	$ 56	$ 140	$ 168