CONSOLIDATED STATEMENTS OF CASH FLOWS - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
CASH FLOWS FROM OPERATING ACTIVITIES
Net income	$ 45,292	$ 107,936	$ 87,296
Adjustments to reconcile net income to net cash from operating activities:
Depreciation	37,919	40,216	43,383
Amortization of intangible assets and debt issuance costs	5,810	15,756	16,027
Share-based compensation expense	9,477	18,615	6,623
Excess income tax benefit from share-based compensation	(186)	(787)	(1,148)
Deferred income taxes	22,214	21,460	9,009
Loss on sale of investments		1,786
(Gain) loss on sale of property and equipment	(2,909)	801	49
Other long-term liabilities	28,912	3,074	23,107
Other non-cash items	(3,680)	3,273	(3,719)
Changes in other components of working capital	(128,777)	(268,808)	(129,899)
NET CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES	14,072	(56,678)	50,728
CASH FLOWS FROM INVESTING ACTIVITIES
Acquisition of property and equipment excluding financed purchases	(35,912)	(75,013)	(42,360)
Proceeds from sale of property and equipment	4,980	5,335	2,663
Proceeds from sale of available-for-sale securities		44,497
Change in restricted cash	(1,483)	(1,776)	(3,877)
NET CASH USED IN INVESTING ACTIVITIES	(32,415)	(26,957)	(43,574)
CASH FLOWS FROM FINANCING ACTIVITIES
Proceeds from debt	1,013,205	1,156,739	653,280
Repayment of debt	(1,054,371)	(1,026,349)	(676,795)
Business acquisition-related payments		(26,430)	(31,038)
Excess income tax benefit from share-based compensation	186	787	1,148
Issuance of common stock and effect of cashless exercise	(808)	(1,771)	(1,882)
Debt issuance costs		(3,681)
NET CASH (USED IN) PROVIDED BY FINANCING ACTIVITIES	(41,788)	99,295	(55,287)
Net (decrease) increase in cash and cash equivalents	(60,131)	15,660	(48,133)
Cash and cash equivalents at beginning of year	135,583	119,923	168,056
Cash and cash equivalents at end of year	$ 75,452	$ 135,583	$ 119,923