Employee Benefit and Deferred Compensation Plans - Components of Net Periodic Benefit Cost (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Pension Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 0	$ 0	$ 0
Interest cost	1,176	1,043	1,168
Expected return on plan assets	(1,450)	(2,077)	(1,941)
Prior service cost recognized	0	0	0
Recognized actuarial loss	442	328	401
Settlement/curtailment/termination losses	0	0	0
Net periodic benefit cost	168	(706)	(372)
Net actuarial (gain) loss arising during the period	(31)	(173)	(1,051)
Net Settlement/curtailment/termination losses	0	0	0
Amortization of net actuarial loss recognized in net periodic pension cost	(442)	(328)	(401)
Total recognized in other comprehensive income	(473)	(501)	(1,452)
Total recognized in net periodic benefit cost and other comprehensive income	$ (305)	$ (1,207)	$ (1,824)
Discount rate used to determine net periodic pension cost	4.56%	3.96%	4.35%
Expected return on plan assets	6.00%	6.00%	8.00%
Other Benefits
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 7	$ 8	$ 9
Interest cost	31	31	42
Expected return on plan assets	0	0	0
Prior service cost recognized	0	0	0
Recognized actuarial loss	(23)	0	6
Settlement/curtailment/termination losses	0	0	0
Net periodic benefit cost	15	39	57
Net actuarial (gain) loss arising during the period	(60)	(240)	(328)
Net Settlement/curtailment/termination losses	0	0	0
Amortization of net actuarial loss recognized in net periodic pension cost	23	0	(6)
Total recognized in other comprehensive income	(37)	(240)	(334)
Total recognized in net periodic benefit cost and other comprehensive income	$ (22)	$ (201)	$ (277)
Discount rate used to determine net periodic pension cost	4.07%	3.37%	3.57%