Fair Value - Quantitative Disclosure for Assets Classified as Level 3 (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance at December 31, 2012
Gains or losses (realized or unrealized) included in net income (loss)	399
Investments and capital calls	7,139
Distributions received	(25)
Transfers into and out of Level 3
Balance at December 31, 2013	7,513
Net Asset Value [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance at December 31, 2012
Gains or losses (realized or unrealized) included in net income (loss)	200
Investments and capital calls	3,139
Distributions received	(25)
Transfers into and out of Level 3
Balance at December 31, 2013	3,314
Equity Method [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Balance at December 31, 2012
Gains or losses (realized or unrealized) included in net income (loss)	199
Investments and capital calls	4,000
Distributions received
Transfers into and out of Level 3
Balance at December 31, 2013	$ 4,199