For the Six Months Ended June 30,  | For the Years Ended December 31,  | ||||||||||||||||||||||
2018  | 2017  | 2016  | 2015  | 2014  | 2013  | ||||||||||||||||||
(in thousands, except ratios)  | |||||||||||||||||||||||
Income (loss) before income taxes  | $  | 432,688  | $  | (343,813  | )  | $  | (1,201,916  | )  | $  | (722,861  | )  | $  | 1,064,699  | $  | 278,611  | ||||||||
Fixed charges  | 96,078  | 193,587  | 167,600  | 155,510  | 117,147  | 102,758  | |||||||||||||||||
Amortization of capitalized interest  | 5,017  | 11,623  | 13,905  | 9,116  | 11,448  | 11,784  | |||||||||||||||||
Capitalized interest  | (10,536  | )  | (12,607  | )  | (17,004  | )  | (25,051  | )  | (16,165  | )  | (10,952  | )  | |||||||||||
Earnings before fixed charges  | $  | 523,247  | $  | (151,210  | )  | $  | (1,037,415  | )  | $  | (583,286  | )  | $  | 1,177,129  | $  | 382,201  | ||||||||
Fixed charges:  | |||||||||||||||||||||||
Interest expense (1)  | $  | 84,739  | $  | 179,257  | $  | 148,685  | $  | 128,149  | $  | 98,554  | $  | 89,711  | |||||||||||
Capitalized interest  | 10,536  | 12,607  | 17,004  | 25,051  | 16,165  | 10,952  | |||||||||||||||||
Interest expense component of rent (2)  | 803  | 1,723  | 1,911  | 2,310  | 2,428  | 2,095  | |||||||||||||||||
Total fixed charges  | $  | 96,078  | $  | 193,587  | $  | 167,600  | $  | 155,510  | $  | 117,147  | $  | 102,758  | |||||||||||
Ratio of earnings to fixed charges  | 5.4  | —  | —  | —  | 10.0  | 3.7  | |||||||||||||||||
Insufficient coverage  | $  | —  | $  | 344,797  | $  | 1,205,015  | $  | 738,796  | $  | —  | $  | —  | |||||||||||
(1)   | Includes amortization of deferred financing costs and debt discount. Interest expense for the year ended December 31, 2016, excludes the $10.0 million paid to terminate a second lien facility that was no longer necessary to fund acquisition activity.  | 
(2)   | Represents a reasonable approximation of the portion of rental expense assumed to be attributable to the interest factor.  |