CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
CASH FLOWS FROM OPERATING ACTIVITIES:
Net income	$ 9,918	$ 8,937
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation and amortization	25,802	27,024
Provision for doubtful accounts	3,343	3,190
Amortization of debt discount and debt issuance costs	321	552
Stock-based compensation	844	1,076
Deferred income taxes		41
Equity in earnings of an unconsolidated affiliate	(582)	(1,402)
Gain on disposition of long-lived assets	(1,076)
Changes in operating assets and liabilities, excluding the effects of acquisitions:
Accounts receivable	772	(2,390)
Materials and supplies, prepayments, and other current assets	(5,893)	(5,184)
Accounts payable and accrued liabilities, advance payments and deposits and other current liabilities	12,024	(11,313)
Accrued taxes	(19,805)	4,507
Other	(687)	(4,010)
Net cash provided by operating activities	24,981	21,028
CASH FLOWS FROM INVESTING ACTIVITIES:
Capital expenditures	(20,876)	(19,055)
Proceeds from disposition of long-lived assets	1,500
Net cash used in investing activities	(19,376)	(19,055)
CASH FLOWS FROM FINANCING ACTIVITIES:
Proceeds from borrowings under revolver loan		27,925
Principal repayments of revolver loan		(15,079)
Payment of debt issuance costs	(5)
Proceeds from stock option exercises	297	103
Principal repayments of term loan		(6,267)
Dividends paid on common stock		(3,553)
Distributions to non-controlling interests	(935)	(424)
Investments made by non-controlling interests	60	450
Purchase of common stock	(879)	(170)
Net cash (used in) provided by financing activities	(1,462)	2,985
NET CHANGE IN CASH AND CASH EQUIVALENTS	4,143	4,958
CASH AND CASH EQUIVALENTS, beginning of the period	136,647	48,735
CASH AND CASH EQUIVALENTS, end of the period	$ 140,790	$ 53,693