CONSOLIDATED STATEMENTS OF CASH FLOWS $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Cash flows from operating activities:
Net income	$ 33,156	$ 59,122	$ 349,205
Adjustments to reconcile net income to net cash flows provided by operating activities:
Depreciation and amortization	56,890	51,234	48,737
Provision for doubtful accounts	1,199	1,676	1,163
Amortization of debt discount and debt issuance costs	458	114	6,681
Stock-based compensation	4,975	4,323	4,454
Loss on interest rate derivative contracts			5,408
Deferred income taxes	17,869	(113)	(4,849)
Income from discontinued operations, net of tax			(5,166)
Gain on disposition of long-lived assets	(2,823)		(1,076)
Gain on sale of discontinued operations	(1,092)	(1,102)	(307,102)
Loss on deconsolidation of subsidiary	19,937
Changes in operating assets and liabilities, excluding the effects of acquisitions:
Accounts receivable, net	11,744	(15,264)	2,233
Materials and supplies, prepayments, and other current assets	(1,094)	(4,817)	(17,117)
Accounts payable and accrued liabilities, advance payments and deposits and other current liabilities	(2,385)	7,629	10,472
Accrued taxes	9,740	(15,650)	(242,696)
Other	(9,494)	(1,833)	4,006
Income tax receivable		(2,620)	14,251
Net cash provided by (used in) operating activities of continuing operations	139,080	82,699	(131,396)
Net cash provided by (used in) operating activities of discontinued operations	158	(4,719)	19,394
Net cash provided by (used in) operating activities	139,238	77,980	(112,002)
Cash flows from investing activities:
Capital expenditures	(64,753)	(58,300)	(69,316)
Acquisition of business	(11,968)	(50,361)
Restricted cash acquired from acquisition of businesses		(5,884)
Net proceeds from sale of assets		1,371
Change in restricted cash	38,877	38,707
Proceeds from disposition of long-lived assets	5,873		1,500
Net cash used in investing activities of continuing operations	(31,971)	(74,467)	(67,816)
Net cash used in investing activities of discontinued operations, net			710,934
Net cash provided by (used in) investing activities	(31,971)	(74,467)	643,118
Cash flows from financing activities:
Dividends paid on common stock	(19,070)	(17,488)	(12,096)
Distribution to minority stockholders	(16,514)	(16,331)	(26,155)
Payment of debt issuance costs	(892)	(1,945)	(12)
Proceeds from stock option exercises	1,998	1,129	2,669
Principal repayments of term loan	(6,017)		(272,137)
Purchase of common stock	(1,893)	(1,665)	(1,473)
Investments made by minority shareholders in consolidated affiliates	950	2,500	408
Repurchase of non-controlling interests		(104)
Net cash provided by financing activities of continuing operations	(41,438)	(33,904)	(308,796)
Net cash provided by financing activities of discontinued operations, net			(1,678)
Net cash used in financing activities	(41,438)	(33,904)	(310,474)
Effect of foreign currency exchange rates on cash and cash equivalents			(682)
Net change in cash and cash equivalents	65,829	(30,391)	219,960
Cash and cash equivalents, beginning of period	326,216	356,607	136,647
Cash and cash equivalents, end of period	392,045	326,216	356,607
Supplemental cash flow information:
Interest paid	2,724	2,930	4,857
Taxes paid	9,636	48,349	256,819
Dividends declared, not paid	$ 5,141	$ 4,618	$ 4,285