Consolidated Statements of Cash Flows - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
OPERATING ACTIVITIES:
Consolidated net (loss) income	$ (24,550)	$ 184,243	$ 150,798
Adjustments to reconcile consolidated net (loss) income to net cash provided by operating activities:
Depreciation and amortization	85,173	87,963	86,924
Impairment of intangible assets	128,127	44,369	33,003
Amortization of deferred financing fees	5,216	10,760	4,350
Amortization of favorable contracts	0	0	71
Amortization of inventory step-up	0	0	4,681
Non-cash stock compensation expense	21,018	15,412	12,997
Non-cash interest expense	0	777	2,778
Non-cash gain on bargain purchase	0	0	(849)
Income from available-for-sale securities	(3,032)	0	0
Deferred income taxes, net	(115,249)	(32,934)	(46,130)
Excess tax benefit from stock compensation	0	0	(47,997)
Loss on extinguishment of debt	0	0	1,243
Gain on sale of available-for-sale security	199	45	237
Other	(307)	(4,888)	0
Changes in operating assets and liabilities:
Trade accounts receivable, net	141,979	(132,617)	40,287
Inventories, net	(8,367)	10,208	(50,729)
Prepaid expenses and other current assets	(14,120)	(6,494)	17,574
Trade accounts payable	(9,223)	6,139	(4,819)
Accrued expenses and other liabilities	42,400	(15,224)	93,229
NET CASH PROVIDED BY OPERATING ACTIVITIES	249,264	167,759	297,648
INVESTING ACTIVITIES:
Payments for acquisitions and equity investments, net of cash acquired	0	0	(24,408)
Proceeds from disposal of assets	4,815	5,966	2,459
Payments for other intangible assets	(200)	(3,950)	(3,835)
Purchases of property, plant and equipment	(95,170)	(74,938)	(27,934)
NET CASH USED IN INVESTING ACTIVITIES	(90,555)	(72,922)	(53,718)
FINANCING ACTIVITIES:
Proceeds under stock option and stock purchase plans	7,594	9,795	11,916
Payments of contingent acquisition liabilities	0	0	(8,991)
Debt financing costs	0	(5,128)	(8,564)
Excess tax benefits from stock compensation	0	0	47,997
Common stock repurchases	0	(45,000)	0
Debt repayment	0	(200,000)	(10,450)
NET CASH PROVIDED BY (USED IN) FINANCING ACTIVITIES	7,594	(240,333)	31,908
Effect of changes in exchange rates on cash and cash equivalents	1,044	2	(251)
INCREASE (DECREASE) IN CASH AND CASH EQUIVALENTS	167,347	(145,494)	275,587
CASH AND CASH EQUIVALENTS AT BEGINNING OF YEAR	200,772	346,266	70,679
CASH AND CASH EQUIVALENTS AT END OF YEAR	$ 368,119	$ 200,772	$ 346,266