Leases (Narrative) (Details) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2020 USD ($) ft²	Sep. 30, 2020 USD ($) ft²
Lessee Lease [Line Items]
Operating lease expiration dates		expiration dates through 2031
Frisco Corporate Headquarter [Member]
Lessee Lease [Line Items]
Lease agreement term	11 years	11 years
Area of space before expand | ft²	31,000	31,000
Area of space after expand | ft²	75,000	75,000
Increase in the operating lease asset, net | $	$ 17.3	$ 17.3
Increase in operating lease liability | $	$ 22.2	$ 22.2
Minimum [Member]
Lessee Lease [Line Items]
Leases termination and renewal option		1 year
Maximum [Member]
Lessee Lease [Line Items]
Leases termination and renewal option		5 years