Summary of Significant Accounting Policies - Additional Information (Details)	12 Months Ended	6 Months Ended
Dec. 31, 2012	Jun. 30, 2013 Maximum [Member]
Accounts, Notes, Loans and Financing Receivable [Line Items]
Written loan commitment period before closing		60 days
Amortization of intangible assets	10 years

Weighted average period before the next renewal or extension (both explicit and implicit) for intangible assets that have been renewed or extended, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (d)(2)

-URI http://asc.fasb.org/extlink&oid=7658586&loc=d3e16323-109275

Name:	us-gaap_FiniteLivedIntangibleAssetWeightedAveragePeriodBeforeNextRenewalOrExtension
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration