Condensed Consolidated Statements of Comprehensive Income (Loss) (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Statement of Comprehensive Income [Abstract]
Net earnings (loss)	$ 10,363us-gaap_NetIncomeLoss	$ (5,321)us-gaap_NetIncomeLoss
Unrealized gain on short-term investments	139	14
Other unrealized gain	24
Changes in pension plan assets and benefit obligations		(1)
Tax effect of preceding losses, gains or changes	(55)us-gaap_OtherComprehensiveIncomeLossTax	(5)us-gaap_OtherComprehensiveIncomeLossTax
Total comprehensive income (loss)	$ 10,471us-gaap_ComprehensiveIncomeNetOfTax	$ (5,313)us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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Amount before tax, after reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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Amount before tax, after reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans.

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Amount of tax expense (benefit) allocated to other comprehensive income (loss).

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Amount before tax and reclassification adjustments of unrealized holding gain (loss) on available-for-sale securities.

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