Employee Benefit Plans Employee Benefit Plans 15 (Details) - SERP - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Components of Net Periodic Benefits Cost:
Service cost	$ 1,193	$ 1,096	$ 930
Interest cost	1,069	888	893
Amortization of prior service cost (credit)	0	0	12
Amortization of actuarial (gain) loss	471	1,049	777
Net periodic pension cost under accounting standards	$ 2,733	$ 3,033	$ 2,612
Weighted-average assumptions used to determine net periodic cost:
Discount rate	4.40%	3.72%	4.34%
Rate of compensation increase	4.00%	4.00%	4.00%