Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended								12 Months Ended
	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Basic:
Net Loss	$ 175	$ 70,596	$ (107,987)	$ (176,296)	$ 9,639	$ 6,278	$ (237,963)	$ (311,253)	$ (213,512)	$ (533,299)	$ (1,054,579)
Less: Net loss allocable to participating RSUs									0	0	0
Net loss available for basic common shares									$ (213,512)	$ (533,299)	$ (1,054,579)
Weighted average common shares outstanding (in shares)	346,727	346,698	345,941	345,852	345,720	345,285	344,584	344,434	346,127	345,012	343,564
Basic net loss per common share (USD per share)	$ 0.00	$ 0.20	$ (0.31)	$ (0.51)	$ 0.03	$ 0.02	$ (0.69)	$ (0.90)	$ (0.62)	$ (1.55)	$ (3.07)
Diluted:
Net Loss	$ 175	$ 70,596	$ (107,987)	$ (176,296)	$ 9,639	$ 6,278	$ (237,963)	$ (311,253)	$ (213,512)	$ (533,299)	$ (1,054,579)
Less: Net loss allocable to participating RSUs									0	0	0
Net loss available for diluted common shares									$ (213,512)	$ (533,299)	$ (1,054,579)
Weighted average common shares outstanding (in shares)	346,727	346,698	345,941	345,852	345,720	345,285	344,584	344,434	346,127	345,012	343,564
Weighted average common equivalent shares arising from:
Dilutive stock options and non-participating RSUs (in shares)									0	0	0
Weighted average number of common and potential common shares (in shares)	348,268	348,487	345,941	345,852	345,846	345,672	344,584	344,434	346,127	345,012	343,564
Diluted net loss per common share (USD per share)	$ 0.00	$ 0.20	$ (0.31)	$ (0.51)	$ 0.03	$ 0.02	$ (0.69)	$ (0.90)	$ (0.62)	$ (1.55)	$ (3.07)