Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2016	Dec. 31, 2015
CURRENT ASSETS:
Cash and cash equivalents	$ 24,971	$ 35,941
Accounts receivable, net	368,704	382,458
Materials and supplies	45,873	45,790
Prepaid expenses and other	47,277	43,197
Total current assets	486,825	507,386
PROPERTY AND EQUIPMENT, net	4,208,706	4,215,063
GOODWILL	815,532	826,575
INTANGIBLE ASSETS, net	1,069,017	1,128,952
DEFERRED INCOME TAX ASSETS, net	2,591	2,270
OTHER ASSETS, net	37,350	22,836
Total assets	6,620,021	6,703,082
CURRENT LIABILITIES:
Current portion of long-term debt	130,450	75,966
Accounts payable	238,181	282,275
Accrued expenses	188,013	169,586
Total current liabilities	556,644	527,827
LONG-TERM DEBT, less current portion	2,035,589	2,205,785
DEFERRED INCOME TAX LIABILITIES, net	983,383	983,136
DEFERRED ITEMS - grants from outside parties	302,269	292,198
OTHER LONG-TERM LIABILITIES	150,312	174,675
COMMITMENTS AND CONTINGENCIES
EQUITY:
Additional paid-in capital	1,369,683	1,355,345
Retained earnings	1,620,094	1,544,676
Accumulated other comprehensive loss	(168,261)	(153,457)
Treasury stock, at cost	(230,400)	(227,808)
Total equity	2,591,824	2,519,461
Total liabilities and equity	6,620,021	6,703,082
Class A Common Stock, $0.01 par value, one vote per share; 180,000,000 shares authorized at June 30, 2016 and December 31, 2015; 70,018,069 and 69,674,185 shares issued and 57,244,493 and 56,945,384 shares outstanding (net of 12,773,576 and 12,728,801 shares in treasury) on June 30, 2016 and December 31, 2015, respectively
EQUITY:
Common Stock	700	697
Class B Common Stock, $0.01 par value, ten votes per share; 30,000,000 shares authorized at June 30, 2016 and December 31, 2015; 793,138 shares issued and outstanding on June 30, 2016 and December 31, 2015.
EQUITY:
Common Stock	$ 8	$ 8

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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Balance Type:	credit
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- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.