Consolidated Statements of Cash Flows (USD $)	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 272,091,000	$ 52,433,000	$ 119,484,000
Adjustments to reconcile net income to net cash provided by operating activities:
Income from equity investment in RailAmerica, net	0	(15,557,000)	0
Depreciation and amortization	141,644,000	73,405,000	66,481,000
Compensation cost related to equity awards	16,951,000	12,151,000	7,776,000
Excess tax benefit from share-based compensation	(6,861,000)	(5,335,000)	(2,820,000)
Deferred income taxes	10,229,000	29,926,000	26,291,000
Net (gain)/loss on sale and impairment of assets	(4,677,000)	(11,225,000)	(5,660,000)
Gain on sale of investments	0	0	(907,000)
Gain on insurance recoveries	(1,465,000)	(5,760,000)	(1,061,000)
Insurance proceeds received	11,053,000	21,479,000	646,000
Contingent forward sale contract mark-to-market expense	0	50,106,000	0
Changes in operating assets and liabilities which provided/(used) cash, net of effect of acquisitions:
Accounts receivable, net	(44,454,000)	(262,000)	(12,307,000)
Materials and supplies	(1,839,000)	(567,000)	(1,206,000)
Prepaid expenses and other	(22,000)	(5,384,000)	3,543,000
Accounts payable and accrued expenses	16,383,000	(30,051,000)	(25,556,000)
Other assets and liabilities, net	4,471,000	5,320,000	(1,235,000)
Net cash provided by operating activities	413,504,000	170,679,000	173,469,000
CASH FLOWS FROM INVESTING ACTIVITIES:
Purchase of property and equipment	(249,318,000)	(231,694,000)	(178,668,000)
Grant proceeds from outside parties	33,913,000	39,632,000	22,642,000
Cash paid for acquisitions, net of cash acquired	0	(1,925,296,000)	(89,935,000)
Insurance proceeds for the replacement of assets	0	370,000	0
Proceeds from the sale of investments	0	0	1,369,000
Proceeds from disposition of property and equipment	6,687,000	15,298,000	9,464,000
Net cash used in investing activities	(208,718,000)	(2,101,690,000)	(235,128,000)
CASH FLOWS FROM FINANCING ACTIVITIES:
Principal payments on long-term borrowings, including capital leases	(471,957,000)	(1,013,166,000)	(533,544,000)
Proceeds from issuance of long-term debt	262,651,000	2,192,916,000	581,394,000
Debt amendment/issuance costs	(2,773,000)	(38,839,000)	(4,742,000)
Net proceeds from Class A common stock issuance	0	234,340,000	0
Net proceeds from TEU issuance	0	222,856,000	0
Net proceeds from Series A-1 Preferred Stock issuance	0	349,418,000	0
Dividends paid on Series A-1 Preferred Stock	(2,139,000)	(4,375,000)	0
Proceeds from employee stock purchases	12,510,000	19,320,000	17,433,000
Excess tax benefit from share-based compensation	6,861,000	5,335,000	2,820,000
Treasury stock acquisitions	(11,095,000)	(4,314,000)	(1,326,000)
Net cash (used in)/provided by financing activities	(205,942,000)	1,963,491,000	62,035,000
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	(740,000)	5,023,000	(524,000)
(DECREASE)/INCREASE IN CASH AND CASH EQUIVALENTS	(1,896,000)	37,503,000	(148,000)
CASH AND CASH EQUIVALENTS, beginning of year	64,772,000	27,269,000	27,417,000
CASH AND CASH EQUIVALENTS, end of year	$ 62,876,000	$ 64,772,000	$ 27,269,000