Note 6 - Stock-Based Compensation (Details) - Tax Short-fall from Share-based Payment Arrangements - USD ($) $ in Thousands	3 Months Ended	9 Months Ended
Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2014
Tax Short-fall from Share-based Payment Arrangements [Abstract]
Tax benefit/(short-fall) of tax deductions in excess of grant-date fair value	$ 17	$ (5,602)	$ (1,177)
Benefit of tax deductions on grant-date fair value	275	6,421	$ 1,177
Total benefit of tax deductions	$ 292	$ 819

Amount of cash outflow for realized tax benefit related to deductible compensation cost reported on the entity's tax return for equity instruments in excess of the compensation cost for those instruments recognized for financial reporting purposes.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 718

-SubTopic 20

-Section 55

-Paragraph 24

-URI http://asc.fasb.org/extlink&oid=32706628&loc=d3e11374-113907

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration