Note 13 - Income Taxes - Reconciliation of Income Tax Expense (Details) - USD ($)	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Tax provision at federal statutory rate	$ 15,726,000	$ 26,092,000	$ 28,072,000
Tax expense from minority interest	71,000	204,000
State, net of federal benefit	(3,213,000)	(2,647,000)	(1,783,000)
Nondeductible expenses	478,000	230,000	156,000
Return to provision	(1,418,000)
Share based payments	(136,000)	(237,000)	1,096,000
Insurance expense	(128,000)	(103,000)	27,000
Revalue tax assets/liabilities due to federal tax reform		(8,488,000)
Other, net	15,000	(338,000)	283,000
Unrecognized tax benefits	586,000	613,000	716,000
Expiration of statute of limitations	(2,222,000)	(1,753,000)	(1,368,000)
Total increases (decreases)	459,000	(7,225,000)	1,597,000
Effective income tax expense	$ 16,185,000	$ 18,867,000	$ 29,669,000