Employee Benefit Plans - Major Categories of Assets in Pension Plan (Details) - DB Pension Plan - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value of Plan Assets	$ 89,172	$ 82,352	$ 72,474
(Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value of Plan Assets	89,172	82,352
(Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value of Plan Assets	0	0
(Level 3)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value of Plan Assets	0	0
Cash and cash equivalents
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value of Plan Assets	2,417	1,367
Cash and cash equivalents | (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value of Plan Assets	2,417	1,367
Cash and cash equivalents | (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value of Plan Assets	0	0
Cash and cash equivalents | (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value of Plan Assets	0	0
Common stocks
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value of Plan Assets	26,422	26,574
Common stocks | (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value of Plan Assets	26,422	26,574
Common stocks | (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value of Plan Assets	0	0
Common stocks | (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value of Plan Assets	0	0
Mutual funds
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value of Plan Assets	60,333	54,411
Mutual funds | (Level 1)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value of Plan Assets	60,333	54,411
Mutual funds | (Level 2)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value of Plan Assets	0	0
Mutual funds | (Level 3)
Defined Benefit Plan Disclosure [Line Items]
Total Fair Value of Plan Assets	$ 0	$ 0