Consolidated Condensed Statements of Cash Flows (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Operating Activities:
Net income	$ 19,820	$ 16,579
Adjustments to reconcile net income to cash provided by (used in) operating activities:
Depreciation and amortization	7,459	7,473
Deferred income tax benefit	(2,483)	(1,804)
Stock compensation	1,358	870
Defined benefit plan (income) expense	(9)	1
Provision of doubtful accounts	125	(4)
Gain on revaluation of financial derivatives	(324)	(557)
Gain from equity investment		(785)
Excess tax benefit from equity awards		(2,173)
(Gain) loss on sale of property and equipment	(8)	24
Changes in operating assets and liabilities:
Accounts receivable	(15,994)	(21,153)
Inventory	(5,762)	457
Prepaid expenses and other assets	(3,905)	(5,786)
Accounts payable	15,522	2,798
Accrued liabilities	(6,970)	904
Net cash provided by (used in) operating activities	8,829	(3,156)
Investing Activities:
Investment in subsidiary, net of cash acquired	(47)	(628)
Proceeds from the sale of property and equipment	181	44
Purchases of property and equipment	(10,403)	(6,769)
Net cash used in investing activities	(10,269)	(7,353)
Financing Activities:
Borrowing of debt		13,455
Repayments of debt	(1,669)	(6,965)
Excess tax benefit from equity awards		2,173
Cash paid for the cancellation of restricted stock	(467)
Proceeds from the exercise of Common Stock options	2,026	1,634
Net cash provided by (used in) financing activities	(110)	10,297
Foreign currency effect	(4,569)	2,978
Net increase (decrease) in cash and cash equivalents	(6,119)	2,766
Cash and cash equivalents at beginning of period	85,700	54,885
Cash and cash equivalents at end of period	79,581	57,651
Supplemental disclosure of cash flow information:
Cash paid for taxes	14,768	4,689
Cash paid for interest	515	725
Supplemental disclosure of non-cash transactions:
Common Stock issued to Board of Directors and employees	$ 673	$ 495