Note 15 - Quarterly Financial Data (Unaudited) - Summary of Quarterly Financial Data (Details) - USD ($) $ / shares in Units, $ 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
Revenue	$ 243,822	$ 232,537	$ 225,168	$ 269,615	$ 409,011	$ 427,497	$ 511,165	$ 401,216
Operating loss	(101,602)	(85,553)	(182,437)	(500,416)	(497,432)	(493,338)	(77,350)	(30,202)	$ (870,008)	$ (1,098,322)	$ 123,744
Loss before reorganization items and income taxes	(106,405)	(86,636)	(302,368)	(522,560)	(512,224)	(524,378)	(99,477)	(35,556)
Net loss	$ (118,371)	$ (106,390)	$ (291,116)	$ (428,412)	$ (321,742)	$ (455,016)	$ (65,121)	$ (30,663)	$ (944,289)	$ (872,542)	$ 68,823
Basic (in dollars per share)	$ (1)	$ (0.90)	$ (2.46)	$ (3.65)	$ (2.75)	$ (3.89)	$ (0.56)	$ (0.51)	$ (7.98)	$ (8.48)	$ 1.28
Diluted (in dollars per share)	$ (1)	$ (0.90)	$ (2.46)	$ (3.65)	$ (2.75)	$ (3.89)	$ (0.56)	$ (0.51)	$ (7.98)	$ (8.48)	$ 1.22