Employee Benefits - Employee Benefits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan wage base	$ 280,000	$ 275,000	$ 270,000
Requisite service period (in years)	3 years
Expenses under defined contribution plan	$ 1,900,000	1,800,000	$ 1,500,000
Base Percentage
Defined Benefit Plan Disclosure [Line Items]
Employer contribution percentage to retirement plan	13.20%
Excess Percentage for amounts above Social Security taxable wage base
Defined Benefit Plan Disclosure [Line Items]
Employer contribution percentage to retirement plan	5.70%
Nonqualified Plan
Defined Benefit Plan Disclosure [Line Items]
Employer contribution percentage to retirement plan	18.90%
Maximum gross annual base salary under plan	$ 500,000
Expenses for NQDC plan	100,000	$ 100,000
Nonqualified Plan | Chief Executive Officer
Defined Benefit Plan Disclosure [Line Items]
Maximum gross annual base salary under plan	$ 700,000