Basis of Presentation and Significant Accounting Policies - Earnings Per Share (Detail) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Net income (numerator)
Net income (numerator)	$ 233,946	$ 469
Weighted average shares - basic	371,543	370,831
Non-vested restricted stock	2,638	2,522
Weighted average shares - diluted	374,181	373,353
Net income per share:
Basic (in dollars per share)	$ 0.63	$ 0.00
Diluted (in dollars per share)	$ 0.63	$ 0.00