Information Pertaining to Held to Maturity Securities With Gross Unrealized Losses (Detail) (Corporate Bonds, USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013
Corporate Bonds
Schedule of Held-to-maturity Securities [Line Items]
Fair Value, Less Than 12 Months	$ 0	$ 28,839
Gross Unrealized Losses, Less Than 12 Months	0	(40)
Fair Value, 12 Months or Longer	0	2,614
Gross Unrealized Losses, 12 Months or Longer	0	(3)
Fair Value	0	31,453
Gross Unrealized Losses	$ 0	$ (43)

Amount of unrealized loss on investments in held-to-maturity securities that have been in a loss position for twelve months or longer.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef

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Amount of unrealized loss on investments in held-to-maturity securities.

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This item represents the fair value of securities categorized as held-to-maturity which are in an unrealized loss position.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

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Amount of unrealized loss before deducting unrealized gain on investments in held-to-maturity securities that have been in a loss position for less than twelve months.

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This item represents the fair value of securities categorized as held-to-maturity that have been in a continuous unrealized loss position for less than twelve months.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

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-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27290-111563

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This item represents the fair value of securities categorized as held-to-maturity securities that have been in a continuous unrealized loss position for twelve months or longer.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 320

-SubTopic 10

-Section 50

-Paragraph 7

-URI http://asc.fasb.org/extlink&oid=27724398&loc=d3e27337-111563

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-Publisher FASB

-Name Accounting Standards Codification

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