Consolidated Condensed Statements of Cash Flows - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Operating Activities:
Net income	$ 40,469	$ 50,562
Adjustments to reconcile net income to cash provided by operating activities:
Depreciation and amortization	32,663	27,724
Deferred income taxes	(9,059)	(1,933)
Stock compensation	8,559	6,856
Defined benefit plan expense	96	151
Provision of doubtful accounts	(353)	385
Loss on sale of property and equipment	868	291
Changes in operating assets and liabilities:
Accounts receivable	(5,581)	(22,835)
Inventory	(4,407)	(5,647)
Prepaid expenses and other assets	(555)	2,826
Accounts payable	(7,433)	6,508
Accrued liabilities	(39,896)	6,123
Net cash provided by operating activities	15,371	71,011
Investing Activities:
Proceeds from the sale of property and equipment	41	45
Acquisition of subsidiary, net of cash acquired	(2,000)	(73,593)
Purchases of property and equipment	(37,181)	(50,742)
Net cash used in investing activities	(39,140)	(124,290)
Financing Activities:
Borrowing of debt		75,000
Repayments of debt	(25,906)	(32,368)
Excess tax expense from equity awards		(277)
Cash paid for financing costs		(650)
Cash paid for the cancellation of restricted stock	(1,100)	(1,196)
Cash paid for the repurchase of common stock	(5,326)
Proceeds from the exercise of Common Stock options	2,434	1,038
Net cash (used in) provided by financing activities	(29,898)	41,547
Foreign currency effect	24,106	66
Net decrease in cash and cash equivalents	(29,561)	(11,666)
Cash and cash equivalents at beginning of period	177,187	144,479
Cash and cash equivalents at end of period	147,626	132,813
Supplemental disclosure of cash flow information:
Cash paid for taxes	67,160	18,183
Cash paid for interest	3,171	1,963
Supplemental disclosure of non-cash transactions:
Common Stock issued to Board of Directors and employees	$ 3,873	$ 3,507