Saving and Retirement Plans 401K Retirement Plan (Details) - USD ($)	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Defined Benefit Plan Disclosure [Line Items]
Defined contribution plan, percentage of employee deferrals to company matching contributions	100.00%
Profit Sharing Contribution, Vesting Period	3 years
Defined Contribution Plan, Cost	$ 3,500,000	$ 3,500,000	$ 3,900,000
Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Employer Discretionary Contribution Amount	$ 5,000