Consolidated Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
CASH FLOWS FROM OPERATING ACTIVITIES:[Abstract]
Net income	$ 52,433	$ 119,484	$ 81,260
Adjustments to reconcile net income to net cash provided by operating activities: [Abstract]
(Loss)/income from discontinued operations	118	9	(2,591)
Income from equity investment in RailAmerica, net	(15,557)	0	0
Depreciation and amortization	73,405	66,481	51,166
Compensation cost related to equity awards	12,151	7,776	7,174
Excess tax benefit from share-based compensation	(5,335)	(2,820)	(1,975)
Deferred income taxes	29,926	26,291	12,009
Stamp duty	0	0	12,625
Net (gain)/loss on sale and impairment of assets	(11,225)	(5,660)	(6,441)
Gain on sale of investments	0	(907)	0
Gain on insurance recoveries	(5,760)	(1,061)	0
Insurance proceeds received	21,479	646	0
Contingent forward sale contract mark-to-market expense	50,106	0	0
Changes in operating assets and liabilities which provided (used) cash, net of effect of acquisitions:
Accounts receivable, net	(262)	(12,307)	(18,402)
Materials and supplies	(567)	(1,206)	(205)
Prepaid expenses and other	(5,384)	3,543	(762)
Accounts payable and accrued expenses	(30,051)	(25,556)	36,243
Other assets and liabilities, net	5,320	(1,235)	1,651
Net cash provided by operating activities from continuing operations	170,797	173,478	171,752
Net cash (used in)/provided by operating activities from discontinued operations	(118)	(13)	933
Net cash provided by operating activities	170,679	173,465	172,685
CASH FLOWS FROM INVESTING ACTIVITIES: [Abstract]
Purchase of property and equipment	(231,694)	(178,668)	(119,840)
Grant proceeds from outside parties	39,632	22,642	40,802
Cash paid for acquisition, net of cash acquired	(1,925,296)	(89,935)	(320,023)
Insurance proceeds for the replacement of assets	370	0	0
Proceeds from sale of investments	0	1,369	208
Proceeds from disposition of property and equipment	15,298	9,464	9,991
Net cash used in investing activities from continuing operations	(2,101,690)	(235,128)	(388,862)
Net cash provided by investing activities from discontinued operations	0	0	1,831
Net cash used in investing activities	(2,101,690)	(235,128)	(387,031)
CASH FLOWS FROM FINANCING ACTIVITIES: [Abstract]
Principal payments on long-term borrowings, including capital leases	(1,013,166)	(533,544)	(82,296)
Proceeds from issuance of long-term debt	2,192,916	581,394	205,446
Debt amendment/issuance costs	(38,839)	(4,742)	(2,514)
Net proceeds from Class A common stock issuance	234,340	0	0
Net proceeds from TEU issuance		0	0
Net proceeds from Series A-1 Preferred Stock issuance	349,418	0	0
Dividends paid on A-1 Preferred Stock	(4,375)	0	0
Proceeds from employee stock purchases	19,320	17,433	18,205
Excess tax benefit from share-based compensation	5,335	2,820	1,975
Treasury stock acquisitions	(4,314)	(1,326)	(850)
Net cash provided by financing activities from continuing operations	1,963,491	62,035	139,966
EFFECT OF EXCHANGE RATE CHANGES ON CASH AND CASH EQUIVALENTS	5,023	(521)	(4,009)
CHANGE IN CASH BALANCES INCLUDED IN CURRENT ASSETS OF DISCONTINUED OPERATIONS	0	1	99
INCREASE/(DECREASE) IN CASH AND CASH EQUIVALENTS	37,503	(148)	(78,290)
CASH AND CASH EQUIVALENTS, beginning of year	27,269	27,417	105,707
CASH AND CASH EQUIVALENTS, end of year	$ 64,772	$ 27,269	$ 27,417