Stock Transactions and Unit Redemptions - Summary of Changes in Carrying Amount of Redeemable Partnership Interest (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Stock Transactions, Parenthetical Disclosures [Abstract]
Balance at beginning of period	$ 66,918	$ 78,839
Consolidated net income allocated to FPUs	2,847us-gaap_TemporaryEquityNetIncome	7,839us-gaap_TemporaryEquityNetIncome
Earnings distributions	(2,968)	(8,863)
Re-allocation of equity due to additional investment by founding/working partners	110	938	1,378
FPUs exchanged	(917)	(6,496)
FPUs redeemed	(8,995)	(4,104)
Other	2,506us-gaap_TemporaryEquityOtherChanges	(1,235)us-gaap_TemporaryEquityOtherChanges
Balance at end of period	$ 59,501	$ 66,918	$ 78,839

Exchange Of Founding Working Partner Interests

No definition available.

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- Definition

Reallocation of equity due to additional investments by founding and working partners.

+ References

No definition available.

+ Details

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- Definition

Redemption of founding working partner interests.

+ References

No definition available.

+ Details

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- Definition

The impact on temporary equity associated with the distribution of earnings.

+ References

No definition available.

+ Details

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- Details

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- Definition

Carrying amount, attributable to parent and noncontrolling interests, of an entity's issued and outstanding stock which is not included within permanent equity. Temporary equity is a security with redemption features that are outside the control of the issuer, is not classified as an asset or liability in conformity with GAAP, and is not mandatorily redeemable. Includes any type of security that is redeemable at a fixed or determinable price or on a fixed or determinable date or dates, is redeemable at the option of the holder, or has conditions for redemption which are not solely within the control of the issuer. Includes stock with a put option held by an ESOP and stock redeemable by a holder only in the event of a change in control of the issuer.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.27(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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- Definition

The portion of net income or loss attributable to temporary equity interest.

+ References

No definition available.

+ Details

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- Definition

This element may be used to disclose other activity associated with temporary equity that is not separately disclosed.

+ References

No definition available.

+ Details

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