Consolidated Balance Sheets - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Current assets:
Cash and cash equivalents	$ 1,412,517	$ 748,476
Short-term investments	28,271	3,409
Accounts receivable, net of allowance for doubtful accounts of $18,228 and $15,675	576,313	396,245
Other current assets	232,027	319,396
Total current assets	2,249,128	1,467,526
Long-term investments	9,243	10,042
Property, plant and equipment, net	9,394,602	7,199,210
Goodwill	4,411,762	2,986,064
Intangible assets, net	2,384,972	719,231
Other assets	241,750	226,298
Total assets	18,691,457	12,608,371
Current liabilities:
Accounts payable and accrued expenses	719,257	581,739
Accrued property, plant and equipment	220,367	144,842
Current portion of capital lease and other financing obligations	78,705	101,046
Current portion of mortgage and loans payable	64,491	67,928
Other current liabilities	159,914	133,140
Total current liabilities	1,242,734	1,028,695
Capital lease and other financing obligations, less current portion	1,620,256	1,410,742
Mortgage and loans payable, less current portion	1,393,118	1,369,087
Senior notes	6,923,849	3,810,770
Other liabilities	661,710	623,248
Total liabilities	11,841,667	8,242,542
Commitments and contingencies (Note 14)
Stockholders' equity:
Preferred stock, $0.001 par value per share: 100,000,000 shares authorized in 2017 and 2016; zero shares issued and outstanding	0	0
Common stock, $0.001 par value per share: 300,000,000 shares authorized in 2017 and 2016; 79,440,404 issued and 79,038,062 outstanding in 2017 and 71,817,430 issued and 71,409,015 outstanding in 2016	79	72
Additional paid-in capital	10,121,323	7,413,519
Treasury stock, at cost; 402,342 shares in 2017 and 408,415 shares in 2016	(146,320)	(147,559)
Accumulated dividends	(2,592,792)	(1,969,645)
Accumulated other comprehensive loss	(785,189)	(949,142)
Retained earnings	252,689	18,584
Total stockholders' equity	6,849,790	4,365,829
Total liabilities and stockholders' equity	$ 18,691,457	$ 12,608,371