Consolidated Statements of Cash Flows (USD $)	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 214,003,000	$ 39,037,000
Adjustments to reconcile net income to net cash provided by operating activities:
Loss from discontinued operations	43,000	27,000
Depreciation and amortization	105,718,000	54,947,000
Compensation cost related to equity awards	13,620,000	5,763,000
Excess tax benefit from share-based compensation	(7,487,000)	(2,842,000)
Deferred income taxes	622,000	29,735,000
Net gain on sale of assets	(3,419,000)	(10,447,000)
Gain on insurance recoveries	(1,465,000)	(5,186,000)
Insurance proceeds received	10,353,000	21,479,000
Contingent forward sale contract mark-to-market expense	0	50,106,000
Changes in assets and liabilities which provided/(used) cash, net of effect of acquisitions:
Accounts receivable, net	(42,607,000)	(2,110,000)
Materials and supplies	(1,105,000)	(1,063,000)
Prepaid expenses and other	(9,910,000)	(3,081,000)
Accounts payable and accrued expenses	(8,178,000)	(10,232,000)
Other assets and liabilities, net	8,538,000	3,405,000
Net cash provided by operating activities from continuing operations	278,726,000	169,538,000
Net cash used in operating activities from discontinued operations	(43,000)	(27,000)
Net cash provided by operating activities	278,683,000	169,511,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(170,435,000)	(170,529,000)
Grant proceeds from outside parties	23,878,000	24,929,000
Cash paid for acquisitions, net of cash acquired	0	(837,000)
Insurance proceeds for the replacement of assets	0	370,000
Proceeds from disposition of property and equipment	3,954,000	13,673,000
Net cash used in investing activities from continuing operations	(142,603,000)	(132,394,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Principal payments on long-term borrowings, including capital leases	(388,018,000)	(215,439,000)
Proceeds from issuance of long-term debt	215,443,000	196,480,000
Debt amendment costs	(1,880,000)	0
Net proceeds from Class A common stock issuance	0	234,361,000
Net proceeds from TEU issuance	0	222,856,000
Proceeds from employee stock purchases	11,026,000	12,088,000
Treasury stock purchases	(10,941,000)	(1,770,000)
Dividends paid on Series A-1 Preferred Stock	(2,139,000)	0
Excess tax benefit from share-based compensation	7,487,000	2,842,000
Net cash (used in)/provided by financing activities from continuing operations	(169,022,000)	451,418,000
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	124,000	227,000
(DECREASE)/INCREASE IN CASH AND CASH EQUIVALENTS	(32,818,000)	488,762,000
CASH AND CASH EQUIVALENTS, beginning of period	64,772,000	27,269,000
CASH AND CASH EQUIVALENTS, end of period	$ 31,954,000	$ 516,031,000