Note 16 - Reportable Segments - Summarized Financial Information (Details) - USD ($)
$ in Thousands
 3 Months Ended 12 Months Ended
Dec. 31, 2016
Sep. 30, 2016
Jun. 30, 2016
Mar. 31, 2016
Dec. 31, 2015
Sep. 30, 2015
Jun. 30, 2015
Mar. 31, 2015
Dec. 31, 2016
Dec. 31, 2015
Dec. 31, 2014
Gross revenues $ 63,022 $ 60,091 $ 55,892 $ 44,905 $ 42,320 $ 48,701 $ 34,481 $ 29,153 $ 223,910 $ 154,655 $ 108,382
Income before taxes 4,981 $ 5,394 $ 4,518 $ 3,253 4,175 $ 4,869 $ 2,729 $ 1,714 18,146 13,487 7,969
Assets 223,659       111,769       223,659 111,769  
Operating Segments [Member] | INF [Member]                      
Gross revenues                 159,514 133,938 98,357
Income before taxes                 27,688 19,010 13,989
Assets 100,481       72,331       100,481 72,331  
Operating Segments [Member] | BES [Member]                      
Gross revenues                 69,218 21,979 10,730
Income before taxes                 7,847 6,181 2,197
Assets 83,328       12,933       83,328 12,933  
Intersegment Eliminations [Member]                      
Gross revenues                 (4,822) (1,262) (705)
Income before taxes                 35,535 25,191 16,186
Corporate, Non-Segment [Member]                      
Income before taxes [1]                 (17,389) (11,704) $ (8,217)
Assets [2] $ 39,850       $ 26,505       $ 39,850 $ 26,505  
[1] Includes amortization of intangibles of $4,549, $2,624 and $1,427 for the years ended December 31, 2016, 2015 and 2014, respectively.
[2] Corporate assets consist of intercomany eliminations and assets not allocated to segments including cash and cash equivalents, deferred income taxes and certain other assets.