Note 6 - Share Option and Equity Incentive Plan (Details) (USD $)	3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended		3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended				6 Months Ended	3 Months Ended	6 Months Ended	3 Months Ended	6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014 Employee Stock Option [Member] The 2013 Plan [Member]	Jun. 30, 2014 Employee Stock Option [Member]	Jun. 30, 2013 Employee Stock Option [Member]	Jun. 30, 2014 Employee Stock Option [Member]	Jun. 30, 2013 Employee Stock Option [Member]	Mar. 31, 2014 Restricted Stock [Member] The 2013 Plan [Member]	Jun. 30, 2014 Restricted Stock [Member] The 2013 Plan [Member]	Jun. 30, 2014 Restricted Stock [Member]	Jun. 30, 2014 Restricted Stock [Member]	Mar. 31, 2014 Second Anniversary of Grant Date [Member] The 2013 Plan [Member]	Mar. 31, 2014 Third Anniversary of Grant Date [Member] The 2013 Plan [Member]	Mar. 31, 2014 Fourth Anniversary of Grant Date [Member] The 2013 Plan [Member]	Jun. 30, 2014 The 2013 Plan [Member]	Jun. 30, 2014 The 2013 Plan [Member]	Jun. 30, 2014 Minimum [Member] The 2013 Plan [Member]	Jun. 30, 2014 Minimum [Member] The 2013 Plan [Member]	Jun. 30, 2014 Maximum [Member] The 2013 Plan [Member]	Jun. 30, 2014 Maximum [Member] The 2013 Plan [Member]
Note 6 - Share Option and Equity Incentive Plan (Details) [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Gross (in Shares)																	95,557	466,452
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Lower Range Limit (in Dollars per share)																			$ 16.86	$ 16.86
Share-based Compensation, Shares Authorized under Stock Option Plans, Exercise Price Range, Upper Range Limit (in Dollars per share)																					$ 19.63	$ 22.99
Share-based Compensation Arrangement by Share-based Payment Award, Options, Grants in Period, Weighted Average Grant Date Fair Value (in Dollars per share)																	$ 8.01	$ 10.37
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period					10 years
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period (in Shares)										254,700	254,700
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value (in Dollars per share)										$ 22.99
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights, Percentage														40.00%	30.00%	30.00%
Allocated Share-based Compensation Expense	$ 760,000	$ 13,000	$ 1,025,000	$ 25,000		$ 483,000	$ 13,000	$ 660,000	$ 25,000			$ 277,000	$ 365,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized						$ 4,800,000		$ 4,800,000				$ 5,200,000	$ 5,200,000
Employee Service Share-based Compensation, Nonvested Awards, Compensation Cost Not yet Recognized, Period for Recognition								2 years 292 days					3 years 255 days