Consolidated Condensed Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Operating Activities:
Net income	$ 29,270	$ 40,469
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	38,721	32,663
Deferred income taxes	(19)	(9,059)
Stock compensation	6,360	8,559
Defined benefit plan (income) expense	(219)	96
Provision of doubtful accounts	247	(353)
Loss on sale of property and equipment	2,273	868
Impairment loss	11,476
Changes in operating assets and liabilities:
Accounts receivable	(13,855)	(5,581)
Inventory	(3,510)	(4,407)
Prepaid expenses and other assets	(7,867)	(555)
Accounts payable	8,376	(7,433)
Accrued liabilities	(712)	(39,896)
Net cash provided by operating activities	70,541	15,371
Investing Activities:
Proceeds from the sale of property and equipment	703	41
Final payment for acquisition of subsidiary, net of cash acquired	(15)	(2,000)
Purchases of property and equipment	(31,815)	(37,181)
Net cash used in investing activities	(31,127)	(39,140)
Financing Activities:
Borrowing of debt	18,000
Repayments of debt	(61,210)	(25,906)
Cash paid for the cancellation of restricted stock	(882)	(1,100)
Proceeds from the exercise of Common Stock options	14,062	2,434
Repurchase of Common Stock	(64,151)	(5,326)
Net cash used in financing activities	(94,181)	(29,898)
Foreign currency effect	(1,253)	24,106
Net decrease in cash and cash equivalents	(56,020)	(29,561)
Cash and cash equivalents at beginning of period	103,172	177,187
Cash and cash equivalents at end of period	47,152	147,626
Supplemental disclosure of cash flow information:
Cash paid for taxes	19,255	67,160
Cash paid for interest	3,617	3,171
Supplemental disclosure of non-cash transactions:
Common Stock issued to Board of Directors and employees	$ 3,893	$ 3,873