Consolidated Balance Sheets (USD $) In Thousands, unless otherwise specified	Mar. 31, 2012	Dec. 31, 2011
CURRENT ASSETS:
Cash and cash equivalents	$ 28,738	$ 27,269
Accounts receivable, net	163,151	165,768
Materials and supplies	16,011	14,445
Prepaid expenses and other	15,844	13,332
Deferred income tax assets, net	19,231	19,385
Total current assets	242,975	240,199
PROPERTY AND EQUIPMENT, net	1,680,034	1,643,589
GOODWILL	160,964	160,277
INTANGIBLE ASSETS, net	229,029	230,628
DEFERRED INCOME TAX ASSETS, net	2,389	2,342
OTHER ASSETS, net	17,984	17,122
Total assets	2,333,375	2,294,157
CURRENT LIABILITIES:
Current portion of long-term debt	59,340	57,168
Accounts payable	121,549	134,081
Accrued expenses	58,446	69,097
Deferred income tax liabilities, net	104	925
Total current liabilities	239,439	261,271
LONG-TERM DEBT, less current portion	577,692	569,026
DEFERRED INCOME TAX LIABILITIES, net	295,922	285,780
DEFERRED ITEMS - grants from outside parties	203,001	198,824
OTHER LONG-TERM LIABILITIES	19,676	18,622
COMMITMENTS AND CONTINGENCIES	0	0
STOCKHOLDERS' EQUITY:
Additional paid-in capital	395,714	385,473
Retained earnings	763,910	741,669
Accumulated other comprehensive income	44,178	37,895
Treasury stock, at cost	(206,708)	(204,952)
Total stockholders' equity	997,645	960,634
Total liabilities and stockholders' equity	2,333,375	2,294,157
Class A
STOCKHOLDERS' EQUITY:
Common Stock	530	527
Class B
STOCKHOLDERS' EQUITY:
Common Stock	$ 21	$ 22