CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 21,339	$ 20,704
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation and amortization	51,255	53,606
Provision for doubtful accounts	5,110	6,325
Amortization of debt discount and debt issuance costs	631	1,747
Stock-based compensation	2,071	1,908
Deferred income taxes		108
Equity in earnings of an unconsolidated affiliate	(976)	(2,331)
Gain on disposition of long-lived assets	(1,076)
Changes in operating assets and liabilities:
Accounts receivable	(7,169)	(10,225)
Materials and supplies, prepayments, and other current assets	(9,124)	(3,401)
Income tax receivable		11,545
Accounts payable and accrued liabilities, advance payments and deposits and other current liabilities	(1,271)	(5,054)
Accrued taxes	(24,723)	9,156
Other	(632)	(4,480)
Net cash provided by operating activities	35,435	79,608
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(52,183)	(32,272)
Proceeds from disposition of long-lived assets	1,500
Net cash used in investing activities	(50,683)	(32,272)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from borrowing under term loan		275,000
Proceeds from borrowings under revolver loan		46,378
Principal repayments of term loan	(3,920)	(252,953)
Principal repayments of revolver loan		(74,534)
Proceeds from stock option exercises	1,232	946
Dividends paid on common stock	(3,919)	(7,119)
Distributions to non-controlling interests	(2,562)	(929)
Payments of debt issuance costs	(12)	(3,564)
Repurchase of non-controlling interests		(80)
Investments made by non-controlling interests	135	805
Purchase of common stock	(915)	(184)
Net cash provided by (used in) financing activities	(9,961)	(16,234)
NET CHANGE IN CASH AND CASH EQUIVALENTS	(25,209)	31,102
CASH AND CASH EQUIVALENTS, beginning of the period	136,647	48,735
CASH AND CASH EQUIVALENTS, end of the period	$ 111,438	$ 79,837