Carrying amount as of the balance sheet date of cash collateral held for borrowed securities, for which the cash is restricted as to withdrawal or usage.

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Notes Payable - Additional Information (Detail) - USD ($) $ in Millions	6 Months Ended		12 Months Ended
	Jun. 30, 2015	Jun. 30, 2014	Dec. 31, 2014
Debt Instrument [Line Items]
Collateral Account used for future payments	$ 0.4		$ 2.4
PIK Notes [Member]
Debt Instrument [Line Items]
Issued aggregate principal amount	19.4		18.5
Runoff Notes [Member]
Debt Instrument [Line Items]
Outstanding amounts of notes	29.2		31.2
13% Senior First Lien Notes [Member]
Debt Instrument [Line Items]
Issued aggregate principal amount	$ 110.0
Notes maturity date	Mar. 19, 2030
Principal payments	$ 3.0		78.9
Cash interest paid on Notes	1.0	$ 4.2
13% Senior Second Lien Notes [Member]
Debt Instrument [Line Items]
Issued aggregate principal amount	$ 20.0
Notes maturity date	Mar. 19, 2030
Principal payments from restricted cash	$ 9.0
Notes Payable [Member]
Debt Instrument [Line Items]
Principal and interest payments	$ 0.4		$ 2.4