Loans Receivable - Overall Statistics for Loan Receivables Portfolio (Detail) (USD $) In Thousands, unless otherwise specified	6 Months Ended	12 Months Ended
Jun. 30, 2013 Investment	Dec. 31, 2012 Investment
Accounts, Notes, Loans and Financing Receivable [Line Items]
Net book value	$ 830,101	$ 141,500
Loans Receivable [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Number of loans	13	7
Principal Balance	851,716	164,180
Net book value	$ 830,101	$ 141,500
Wtd. Avg. cash coupon	L+4.38 %	L+2.51 %
Wtd. Avg. all-in yield	L+5.27 %	L+4.53 %
Wtd. Avg. maximum maturity (years)	3 years 8 months 12 days	8 months 12 days

Amount after allowance and deduction of deferred interest and fees, unamortized costs and premiums and discounts from face amounts, of loans and leases held in portfolio, including but not limited to, commercial and consumer loans. Excludes loans and leases covered under loss sharing agreements and loans held for sale.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 310

-SubTopic 10

-Section 45

-Paragraph 2

-URI http://asc.fasb.org/extlink&oid=28367877&loc=d3e4428-111522

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.7)

-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant