Investments - Summary of Fair Value, Unfunded Commitments and Redemption Frequency (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	12 Months Ended
Mar. 31, 2014	Dec. 31, 2013
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Fair Value	$ 646,765	$ 569,293
Gated/Side Pocket Investments	2,649	3,150
Investments without Gates or Side Pockets	644,116	566,143
Unfunded Commitments	131,950	114,240
Private Equity Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Fair Value	191,452	161,229
Gated/Side Pocket Investments
Investments without Gates or Side Pockets	191,452	161,229
Unfunded Commitments	131,295	113,585
Redemption Frequency	Not eligible	Not eligible
Fixed Income Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Fair Value	222,004	194,375
Gated/Side Pocket Investments
Investments without Gates or Side Pockets	222,004	194,375
Unfunded Commitments
Redemption Frequency	Daily to monthly	Daily to monthly
Fixed Income Hedge Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Fair Value	69,547	68,157
Gated/Side Pocket Investments	2,649	3,150
Investments without Gates or Side Pockets	66,898	65,007
Unfunded Commitments
Redemption Frequency	Quarterly after lock-up periods expire	Quarterly after lock-up periods expire
Equity Funds [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Fair Value	128,110	109,355
Gated/Side Pocket Investments
Investments without Gates or Side Pockets	128,110	109,355
Unfunded Commitments
Redemption Frequency	Bi-monthly	Bi-monthly
Real Estate Debt Fund [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Fair Value	32,469	32,113
Gated/Side Pocket Investments
Investments without Gates or Side Pockets	32,469	32,113
Unfunded Commitments
Redemption Frequency	Monthly	Monthly
Other [Member]
Fair Value, Investments, Entities that Calculate Net Asset Value Per Share [Line Items]
Total Fair Value	3,183	4,064
Gated/Side Pocket Investments
Investments without Gates or Side Pockets	3,183	4,064
Unfunded Commitments	$ 655	$ 655
Redemption Frequency	Not eligible	Not eligible

Fair Value Investments Entities That Calculate Net Asset Value Per Share Gated Or Side Pocket Investments

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- Definition

Fair Value Investments Entities That Calculate Net Asset Value Per Share Investments Without Gates Or Side Pockets

+ References

No definition available.

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- Definition

Fair value of investments in certain entities that calculate net asset value per share, including, but not limited to, by unit, membership interest, or other ownership interest. Investments include, but are not limited to, investments in certain hedge funds, venture capital funds, private equity funds, real estate partnerships or funds.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 2

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=25499696&loc=d3e19207-110258

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 6A

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=25499696&loc=SL6742756-110258

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- Definition

States the frequency (for example, annually, semi-annually, quarterly) with which the entity can redeem its investment, or portion thereof, for each of those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments), by major category.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 6A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=25499696&loc=SL6742756-110258

+ Details

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- Definition

The amount of unfunded commitments for which the entity is obligated, to those certain investments for which net asset value per share is calculated (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 820

-SubTopic 10

-Section 50

-Paragraph 6A

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=25499696&loc=SL6742756-110258

+ Details

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