Note 10 - Segment Disclosures - Summary of Intangible Assets and Goodwill (Details) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016	Sep. 30, 2016	Dec. 31, 2015
Other intangibles	$ 298,383	$ 298,383
Goodwill	46,225	47,342	$ 47,342	$ 47,342
Total assets	1,473,807	1,498,149
Motorsports Event Segment [Member]
Other intangibles	298,383	298,383
Goodwill	46,225	47,342
Total assets	1,449,981	1,474,127
Other Segments [Member]
Other intangibles
Goodwill
Total assets	$ 23,826	$ 24,022