Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 376,037	$ 156,233
Accounts receivable, net of allowance for bad debts	256,730	247,028
Prepaid expenses and other current assets	157,625	102,146
Assets held for sale	96,261	400
Total current assets	886,653	505,807
Drilling and other property and equipment, net of accumulated depreciation	5,261,641	5,726,935
Other assets	102,276	139,135
Total assets	6,250,570	6,371,877
Current liabilities:
Accounts payable	38,755	30,242
Accrued liabilities	154,655	182,159
Taxes payable	29,878	23,898
Short-term borrowings	0	104,200
Total current liabilities	223,288	340,499
Long-term debt	1,972,225	1,980,884
Deferred tax liability	167,299	197,011
Other liabilities	113,497	103,349
Total liabilities	2,476,309	2,621,743
Commitments and contingencies (Note 11)
Stockholders' equity:
Preferred stock (par value $0.01, 25,000,000 shares authorized, none issued and outstanding)
Common stock (par value $0.01, 500,000,000 shares authorized; 144,085,292 shares issued and 137,227,782 shares outstanding at December 31, 2017; 143,997,757 shares issued and 137,169,663 shares outstanding at December 31, 2016)	1,441	1,440
Additional paid-in capital	2,011,397	2,004,514
Retained earnings	1,964,497	1,946,765
Accumulated other comprehensive gain (loss)	(5)	1
Treasury stock, at cost (6,857,510 and 6,828,094 shares of common stock at December 31, 2017 and 2016, respectively)	(203,069)	(202,586)
Total stockholders' equity	3,774,261	3,750,134
Total liabilities and stockholders' equity	$ 6,250,570	$ 6,371,877