Note 2 - Significant Accounting Policies (Details Textual) - USD ($)	3 Months Ended	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Depreciation		$ 140,300,000	$ 140,600,000	$ 131,800,000
Amortization		17,600,000	17,000,000	13,100,000
Capitalized Computer Software, Net	$ 31,900,000	31,900,000	33,000,000
Capitalized Computer Software, Accumulated Amortization	20,000,000	20,000,000	16,500,000
Indefinite-Lived Franchise Rights			7,000,000
Goodwill, Impairment Loss	0
Advertising Expense		9,500,000	6,800,000	8,800,000
Income Tax Expense (Benefit)		(35,730,000)	25,867,000	41,750,000
Accounting Standards Update 2016-09 [Member]
Income Tax Expense (Benefit)		(5,300,000)
Vehicles [Member]
Depreciation		107,900,000	106,300,000	101,100,000
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Other Property, Plant, and Equipment, Net	79,800,000	79,800,000
Capital Leases, Lessee Balance Sheet, Assets by Major Class, Property, Plant, and Equipment Other, Accumulated Depreciation	38,700,000	38,700,000
Computer Software, Intangible Asset [Member]
Interest Costs Capitalized		$ 85,500
Impairment of Intangible Assets, Indefinite-lived (Excluding Goodwill)	$ 0
Finite-Lived Intangible Asset, Useful Life		15 years
Amortization of Intangible Assets		$ 3,400,000	$ 3,400,000	$ 3,300,000