Note 13 - Unaudited Quarterly Financial Data - Summarized Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ in Thousands	1 Months Ended	2 Months Ended	3 Months Ended							10 Months Ended	12 Months Ended
	Nov. 14, 2017	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Nov. 14, 2017	Dec. 31, 2016	Dec. 31, 2015
Marine Services Revenue		$ 13,593
Operating loss		(21,859)
Net loss		$ 3,511
Per share (basic) (in dollars per share)		$ 0.35
Per share (diluted) (in dollars per share)		$ 0.35
Predecessor [Member]
Marine Services Revenue	$ 13,424		$ 25,805	$ 24,641	$ 24,359	$ 26,617	$ 27,821	$ 30,487	$ 38,794	$ 88,229	$ 123,719	$ 274,806
Operating loss	(9,308)		(18,202)	(30,680)	(31,992)	(16,965)	(19,766)	(66,338)	(128,256)	(90,182)	(231,325)	(183,552)
Net loss	$ (210,914)		$ (24,643)	$ (40,547)	$ (124,815)	$ (39,488)	$ (24,729)	$ (47,580)	$ (91,182)	$ (400,919)	$ (202,979)	$ (215,235)
Per share (basic) (in dollars per share)	$ (8.13)		$ (0.94)	$ (1.58)	$ (4.93)	$ (1.57)	$ (0.98)	$ (1.90)	$ (3.66)	$ (15.47)	$ (8.09)	$ (8.70)
Per share (diluted) (in dollars per share)	$ (8.13)		$ (0.94)	$ (1.58)	$ (4.93)	$ (1.57)	$ (0.98)	$ (1.90)	$ (3.66)	$ (15.47)	$ (8.09)	$ (8.70)