Consolidated Statements Of Comprehensive Income (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Consolidated Statements Of Comprehensive Income [Abstract]
Net income	$ 82,442us-gaap_NetIncomeLoss	$ 111,159us-gaap_NetIncomeLoss	$ 56,607us-gaap_NetIncomeLoss
Other comprehensive income (loss):
Foreign currency translation adjustments	(1,598)	591	993
Unrealized gain on investments, net of tax	1,369	418	1,476
Other	(152)	433	445
Other comprehensive income (loss)	(381)	1,442	2,914
Comprehensive income	$ 82,061us-gaap_ComprehensiveIncomeNetOfTax	$ 112,601us-gaap_ComprehensiveIncomeNetOfTax	$ 59,521us-gaap_ComprehensiveIncomeNetOfTax

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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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Amount after tax and 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 after tax and reclassification adjustments of other comprehensive income (loss).

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

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