New Accounting Pronouncements (Condensed Consolidated Cash Flow) (Details) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Cash flows from operating activities:
Net income (loss)	$ 10,943	$ 18,074	$ (12,698)	$ 26,629
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation			19,373	18,414
Amortization			5,710	5,903
Deferred income taxes			10,936	1,360
Gain on the sale of property, plant and equipment			(116)	(167)
Stock-based compensation expense			5,405	4,505
Changes in operating assets and liabilities:
Accounts receivable			(8,980)	49,394
Contract assets			(1,735)	3,466
Inventories			(52,063)	(39,478)
Prepaid expenses and other assets			1,966	(7,233)
Accounts payable			23,103	16,675
Accrued liabilities			(16,025)	13,388
Income taxes			8,846	(327)
Net cash provided by operations			(16,182)	92,529
Cash flows from investing activities:
Net cash used in investing activities			(40,564)	(25,999)
Cash flows from financing activities:
Net provided by financing activities			(89,519)	(903)
Effect of exchange rate changes			(642)	2,251
Net increase in cash and cash equivalents			(146,907)	67,878
Cash and cash equivalents at beginning of year			742,546	681,433
Cash and cash equivalents at end of period	$ 595,639	749,311	$ 595,639	749,311
Accounting Standards Update 2014-09 [Member] | As Previously Reported [Member] | Calculated Under Revenue Guidance In Effect Before Topic 606 [Member]
Cash flows from operating activities:
Net income (loss)		17,176		26,863
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation				18,414
Amortization				5,903
Deferred income taxes				2,103
Gain on the sale of property, plant and equipment				(167)
Stock-based compensation expense				4,505
Changes in operating assets and liabilities:
Accounts receivable				49,394
Contract assets				0
Inventories				(34,218)
Prepaid expenses and other assets				(9,658)
Accounts payable				16,675
Accrued liabilities				13,388
Income taxes				(673)
Net cash provided by operations				92,529
Cash flows from investing activities:
Net cash used in investing activities				(25,999)
Cash flows from financing activities:
Net provided by financing activities				(903)
Effect of exchange rate changes				2,251
Net increase in cash and cash equivalents				67,878
Cash and cash equivalents at beginning of year				681,433
Cash and cash equivalents at end of period		749,311		749,311
Accounting Standards Update 2014-09 [Member] | Restatement Adjustment [Member] | Adjustments [Member]
Cash flows from operating activities:
Net income (loss)		898		(234)
Adjustments to reconcile net income (loss) to net cash provided by (used in) operating activities:
Depreciation				0
Amortization				0
Deferred income taxes				(743)
Gain on the sale of property, plant and equipment				0
Stock-based compensation expense				0
Changes in operating assets and liabilities:
Accounts receivable				0
Contract assets				3,466
Inventories				(5,260)
Prepaid expenses and other assets				2,425
Accounts payable				0
Accrued liabilities				0
Income taxes				346
Net cash provided by operations				0
Cash flows from investing activities:
Net cash used in investing activities				0
Cash flows from financing activities:
Net provided by financing activities				0
Effect of exchange rate changes				0
Net increase in cash and cash equivalents				0
Cash and cash equivalents at beginning of year				0
Cash and cash equivalents at end of period		$ 0		$ 0