Carrying Value of Investments in Merchant Banking Funds (Detail) (USD $) In Thousands, unless otherwise specified	Jun. 30, 2012	Dec. 31, 2011
Schedule of Investments [Line Items]
Investments in merchant banking funds	$ 48,256	$ 39,535
GCP Europe
Schedule of Investments [Line Items]
Investments in merchant banking funds	32,022	23,951
GCP II
Schedule of Investments [Line Items]
Investments in merchant banking funds	1,491	1,609
GCP II subject to Put Options
Schedule of Investments [Line Items]
Investments in merchant banking funds	11,127	10,520
Other Merchant Banking Funds
Schedule of Investments [Line Items]
Investments in merchant banking funds	$ 3,616	$ 3,455

Total investments in (A) an entity in which the entity has significant influence, but does not have control, (B) subsidiaries that are not required to be consolidated and are accounted for using the equity and or cost method, and (C) an entity in which the reporting entity shares control of the entity with another party or group. Includes long-term advances receivable from a party that is affiliated with the reporting entity by means of direct or indirect ownership.

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 210.5-02.12)

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

Name:	us-gaap_InvestmentsInAffiliatesSubsidiariesAssociatesAndJointVentures
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant