Employee Benefit Plans - Stock Incentive Plans (Details) - Stock Incentive Plans - USD ($)	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Stock incentive plans
Period of stock options and restricted stock issued	10 years
Common stock reserved for future issuance	8,000,000
Number of shares available for grant	4,729,863
Pre-tax stock-based employee compensation expense	$ 8,630,000	$ 9,419,000	$ 11,090,000
After tax stock-based employee compensation expense	$ 6,516,000	$ 7,111,000	$ 7,042,000