Loan Securitization (Narrative) (Detail) (USD $)	3 Months Ended						0 Months Ended	3 Months Ended	0 Months Ended
	Jun. 30, 2012	Mar. 31, 2012	Sep. 30, 2009	Sep. 30, 2013	Dec. 31, 2012	Sep. 30, 2012	Aug. 15, 2012 Class A [Member]	Sep. 30, 2009 Class A [Member]	Aug. 15, 2012 Class B and C [Member]	Sep. 30, 2013 Securitization Entity [Member]	Dec. 31, 2012 Securitization Entity [Member]	Sep. 30, 2012 Securitization Entity [Member]
Debt Instrument [Line Items]
Instruments issued by the securitization entity								$ 600,000,000
Debt Instrument, Description of Variable Rate Basis			One-month LIBOR
Incremental interest rate over base rate								1.45%
Company repurchased notes	67,200,000	172,000,000					360,800,000		49,600,000
Total loans										0	0	0
Secured borrowings-owed to securitization investors	360,800,000			0	0	0
Proceeds from Secured Debt Intercompany							239,200,000
Cash										36,000	36,000	1,800,000
Other borrowings				$ 246,870,000	$ 274,411,000	$ 377,229,000				$ 0	$ 0	$ 0