Summary of Other Noninterest Income (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Other Income and Expenses [Abstract]
Unused commitment fees	$ 13,006,000		$ 7,095,000		$ 6,833,000
Fund management fees	11,057,000		10,730,000		10,753,000
Service-based fee income	7,937,000		9,717,000		8,840,000
Net gains on the sale of certain assets related to our equity management services business	4,243,000		0		0
Loan syndication fees	3,896,000		1,020,000		1,775,000
Currency revaluation losses	(16,000)	[1]	(4,275,000)	[1]	959,000	[1]
Gains (losses) on revaluation of foreign currency instruments	1,677,000	[2]	(2,096,000)	[2]	(374,000)	[2]
Other	12,601,000		7,964,000		6,856,000
Total other noninterest income	54,401,000		30,155,000		35,642,000
unused commitment fees included in interest income			5,200,000		4,800,000
Foreign currency gains (losses) attributable to noncontrolling interests	$ 0		$ (2,900,000)		$ 400,000

[1] the revaluation of foreign currency denominated financial statements of certain funds. Included in these amounts are gains of $27 thousand, losses of $2.9 million and gains of $0.4 million in 2012, 2011 and 2010, respectively, attributable to noncontrolling interests calculated based on the ownership percentages of the noncontrolling interests.

[2] Represents the revaluation of foreign currency denominated financial instruments issued and held by us, primarily loans, deposits and cash.