Note 2 - Summary of Significant Accounting Policies - Impact of the Adoption on the Company's Previously Reported Results (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Mar. 31, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Scenario, Previously Reported [Member] | New Accounting Pronouncement, Early Adoption, Effect [Member]
Provision for income taxes		$ 5,837
Net income		9,687
Comprehensive income, net of tax		$ 8,770
Basic (in dollars per share)		$ 0.51
Diluted (in dollars per share)		$ 0.50
Diluted (in shares)		19,293
Net cash used in operating activities		$ (13,581)
Net cash provided by financing activities		18,928
New Accounting Pronouncement, Early Adoption, Effect [Member]
Provision for income taxes		5,633
Net income		9,891
Comprehensive income, net of tax		$ 8,974
Basic (in dollars per share)		$ 0.52
Diluted (in dollars per share)		$ 0.51
Diluted (in shares)		19,273
Net cash used in operating activities		$ (13,377)
Net cash provided by financing activities		$ 18,724
Provision for income taxes	$ 8,664		$ 7,226	$ 20,555	$ 18,374
Net income	13,437		11,545	33,911	28,619
Comprehensive income, net of tax	$ 13,272		$ 7,645	$ 30,803	$ 24,130
Basic (in dollars per share)	$ 0.71		$ 0.60	$ 1.79	$ 1.47
Diluted (in dollars per share)	$ 0.70		$ 0.59	$ 1.75	$ 1.45
Diluted (in shares)	19,329		19,556	19,345	19,743
Net cash used in operating activities				$ 57,818	$ 42,901
Net cash provided by financing activities				$ (44,672)	$ (36,208)