Note 8 - Income Taxes (Details Textual) - USD ($)	3 Months Ended		12 Months Ended
	Mar. 31, 2017	Mar. 31, 2016	Dec. 31, 2016
Unrecognized Tax Benefits that Would Impact Effective Tax Rate	$ 2,400,000		$ 2,400,000
Unrecognized Tax Benefits, Income Tax Penalties Accrued	0		0
Unrecognized Tax Benefits, Interest on Income Taxes Expense	145,000		$ 145,000
Income Tax Expense (Benefit)	7,579,000	$ 1,547,000
Accounting Standards Update 2016-09 [Member]
Income Tax Expense (Benefit)	$ (1,100,000)
Domestic Tax Authority [Member] | Earliest Tax Year [Member]
Open Tax Year	2013
Domestic Tax Authority [Member] | Latest Tax Year [Member]
Open Tax Year	2016
State and Local Jurisdiction [Member] | Earliest Tax Year [Member]
Open Tax Year	2012
State and Local Jurisdiction [Member] | Latest Tax Year [Member]
Open Tax Year	2016