Employee Savings Plan (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Employee Savings Plan [Abstract]
Compensation and Employee Benefit Plans [Text Block]	NOTE 11· Employee Savings PlanThe Company has an Employee Savings Plan (401(k)) in which substantially all employees with more than 30 days of service are eligible to participate. Under this plan, the Company makes matching contributions of up to 4.0% of each participant’s annual compensation. Prior to 2014, the Company’s matching contribution was up to 2.5% of each participant’s annual compensation with an additional discretionary profit-sharing contribution each year, which equaled 1.5% of each eligible employee’s compensation. The Company’s contribution expense to the plan totaled $22.8 million in 2018, $19.6 million in 2017 and $19.3 million in 2016.
Service Period Eligible to Participate for Employee Savings Plan	$ 30
Defined Contribution Plan, Employer Matching Contribution, Percent of Match	4.00%		2.50%
Discretionary Profit Sharing Contribution Percentage of Employees Salary	1.50%
Defined Benefit Plan, Plan Assets, Contributions by Employer	$ 22,800,000	$ 19,600,000	$ 19,300,000