Unaudited Consolidated Statements of Comprehensive Income (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2013	Mar. 31, 2012
Unaudited Consolidated Statements of Comprehensive Income [Abstract]
Net income	$ 14,943	$ 11,506
Unrealized net gains on securities:
Unrealized net gains arising during the period	7,803	7,639
Less: reclassification adjustment for net gains included in net income	6,912	(26)
Change in unrealized gains on investments	891	7,665
Foreign currency translation adjustments	(186)	204
Other Comprehensive Income (Loss), Net of Tax	705	7,869
Comprehensive income	$ 15,648	$ 19,375

The change in equity [net assets] of a business enterprise during a period from transactions and other events and circumstances from non-owner sources which are attributable to the economic entity, including both controlling (parent) and noncontrolling interests. It includes all changes in equity during a period except those resulting from investments by owners and distributions to owners, including any and all transactions which are directly or indirectly attributable to that ownership interest in subsidiary equity which is not attributable to the parent.

+ References+ Details

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

+ References

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+ Details

- Definition

Amount of tax effect, net of reclassification adjustments, on the result from the process of expressing in the reporting currency of the reporting entity those amounts that are denominated or measured in a different currency, attributable to the parent entity.

+ References

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+ Details

- Definition

Net of tax amount of the income statement impact of the reclassification adjustment for unrealized gain (loss) realized upon the sale of available-for-sale securities.

+ References

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+ Details

- Definition

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

+ References

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+ Details