Employee Benefit Plans - Cost Components of Supplemental Executive Retirement Plan (Details) - SERP - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 1,731	$ 1,933
Interest cost	575	470
Net pension expense (benefit)	$ 2,306	$ 2,403