Employee Benefit Plans - SERP (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Proceeds from benefit plan financing arrangement	$ 507,000	$ 2,218,000
Supplemental Retirement Plan ('SERP')
Defined Benefit Plan Disclosure [Line Items]
Variable life insurance policies investment amount	55,300,000	47,900,000
Fair value of plan assets	28,476,000	22,815,000
Trading (losses) gains related to the SERP assets	5,524,000	$ (2,282,000)	$ 3,156,000
Cash Surrender Value of Life Insurance	377,000
Proceeds from benefit plan financing arrangement	507,000
Life insurance, tax free gains	$ 126,000