Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
ASSETS
Cash and cash equivalents	$ 527,435	$ 248,204
Restricted cash	12,175	28,285
Marketable Securities	24,292	21,668
Receivables:
Trade, net of allowance for doubtful accounts of $3,652 and $4,212 in 2011 and 2010, respectively	215,768	224,944
Other Receivables, Net, Current	48,181	45,334
Inventory, Net	27,615	25,787
Deferred income taxes	116	3,530
Prepaid expenses and other	6,701	12,719
Assets of Disposal Group, Including Discontinued Operation, Current	0	108,153
Total current assets	862,283	718,624
Property and Equipment	2,199,183	2,238,383
Accumulated depreciation	866,330	763,803
Property, Plant and Equipment, Net In Service	1,332,853	1,474,580
Construction in Progress, Gross	143,482	110,296
Net property and equipment	1,476,335	1,584,876
Investments, at Equity, and Advances to 50% or Less Owned Companies	440,853	272,535
Construction Reserve Funds & Title XI Reserve Funds	261,739	195,629
Goodwill	17,985	17,978
Intangible Assets, Net	12,423	15,305
Other Assets, net of allowance for doubtful accounts of $1,830 in 2010	44,615	55,123
Assets of Disposal Group, Including Discontinued Operation, Noncurrent	0	840,724
Total Assets	3,116,233	3,700,794
LIABILITIES AND EQUITY
Current portion of long-term debt	45,323	21,920
Accounts payable and accrued expenses	85,477	107,892
Accrued wages and benefits	29,510	19,303
Accrued interest	5,849	5,226
Accrued income taxes	17,733	8,089
Short sales of marketable securities	10,697	8,277
Accrued capital, repair and maintenance expenditures	19,975	8,013
Deferred revenues	6,592	6,592
Other current liabilities	33,263	40,493
Discontinued operations	0	39,836
Total current liabilities	254,419	265,641
Long-Term Debt	834,118	655,309
Deferred Income Taxes	457,827	426,027
Deferred Gains and Other Liabilities	144,441	120,401
Liabilities of Disposal Group, Including Discontinued Operation, Noncurrent	0	490,741
Total liabilities	1,690,805	1,958,119
Equity:
Preferred stock, $.01 par value, 10,000,000 shares authorized; none issued nor outstanding	0	0
Common stock, $.01 par value, 60,000,000 shares authorized; 37,219,201 and 36,740,324 shares issued in 2013 and 2012, respectively	372	367
Additional paid-in capital	1,394,621	1,330,324
Retained earnings	1,095,270	1,473,509
Shares held in treasury of 16,837,113 and 16,852,391 in 2011 and 2010, respectively, at cost	1,088,219	1,088,560
Accumulated Other Comprehensive Income (Loss), Net of Tax	(1,192)	(1,986)
Stockholders' equity attributable to parent, total	1,400,852	1,713,654
Noncontrolling interests in subsidiaries	24,576	29,021
Total equity	1,425,428	1,742,675
Liabilities and stockholders' equity, total	$ 3,116,233	$ 3,700,794