Fair Value Measurements - Investments Classified as Available-for-Sale (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013
Available-for-sale Securities, Balance Sheet, Reported Amounts [Abstract]
Available-for-sale Debt Securities, Amortized Cost	$ 202,266
Available-for-sale Equity Securities, Amortized Cost	4,493
Available-for-sale Investments, Amortized Cost	206,759	203,479
Available for sale Investments, Debt Securities, Gross Unrealized Gain	30
Available for sale Investments, Equity Securities, Gross Unrealized Gain	2,076
Available-for-sale Investments,Unrealized Gross Gain	2,106	24
Available for sale Investments, Debt Securities, Gross Unrealized Loss	(9)
Available for sale Investments, Equity Securities, Gross Unrealized Loss	0
Available-for-sale Investments, Gross Unrealized Loss,	(9)	(23)
Available-for-sale Securities, Debt Securities, Fair Value	202,287
Available-for-sale Securities, Equity Securities, Fair Value	6,569
Available-for-sale Investments, Fair Value	$ 208,856	$ 203,480

Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

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-Publisher FASB

-Name Accounting Standards Codification

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt securities classified as available-for-sale.

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in equity securities classified as available-for-sale.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in equity securities classified as available-for-sale.

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Amount of investment in debt and equity securities categorized neither as held-to-maturity nor trading.

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Amount before tax of unrealized gain in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Amount before tax of unrealized loss in accumulated other comprehensive income (AOCI) on investments in debt and equity securities classified as available-for-sale.

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Amount of debt securities categorized neither as held-to-maturity nor trading.

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Amount of equity securities categorized neither as held-to-maturity nor as trading.

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