Derivative Financial Instruments - Components of (Expense) Income of Derivative Financial Instruments (Detail) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative (loss) gain	$ (13,167)	$ 121	$ (5,594)
Free standing warrants assets, related party [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative (loss) gain		(51)	(338)
Free standing warrants liabilities [Member]
Schedule Of Loans And Allowance For Loan By Class Individually And Collectively Evaluated For Impairment [Line Items]
Derivative (loss) gain	$ (13,167)	$ 172	$ (5,256)