CONDENSED CONSOLIDATED BALANCE SHEETS (Unaudited) - USD ($) $ in Thousands	Jun. 30, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 40,132	$ 35,152
Accounts receivable, net of allowance for doubtful accounts of $3,116 and $3,191 at June 30, 2017 and December 31, 2016, respectively	433,366	148,091
Federal and state income taxes receivable	3,666	2,126
Inventory	36,132	20,191
Other	58,453	41,322
Total current assets	571,749	246,882
Property and equipment, net	4,232,194	3,408,963
Goodwill and intangible assets	540,273	88,966
Deposits on equipment purchases	12,917	16,050
Deferred tax assets, net	1,339	4,124
Other	45,584	7,306
Total assets	5,404,056	3,772,291
Current liabilities:
Accounts payable	255,327	125,667
Accrued expenses	217,521	139,148
Total current liabilities	472,848	264,815
Borrowings under revolving credit facility	115,000
Long-term debt, net of debt issuance cost of $1,390 and $1,563 at June 30, 2017 and December 31, 2016, respectively	598,610	598,437
Deferred tax liabilities, net	588,594	650,661
Other	11,201	9,654
Total liabilities	1,786,253	1,523,567
Commitments and contingencies (see Note 11)
Stockholders' equity:
Preferred stock, par value $.01; authorized 1,000,000 shares, no shares issued
Common stock, par value $.01; authorized 300,000,000 shares with 256,914,385 and 191,525,872 issued and 213,328,565 and 148,133,255 outstanding at June 30, 2017 and December 31, 2016, respectively	2,569	1,915
Additional paid-in capital	2,575,401	1,042,696
Retained earnings	1,953,023	2,116,341
Accumulated other comprehensive income (loss)	1,854	(1,134)
Treasury stock, at cost, 43,585,820 and 43,392,617 shares at June 30, 2017 and December 31, 2016, respectively	(915,044)	(911,094)
Total stockholders' equity	3,617,803	2,248,724
Total liabilities and stockholders' equity	$ 5,404,056	$ 3,772,291