Commitments and Contingencies - Additional Information (Detail) (USD $)	9 Months Ended		1 Months Ended	9 Months Ended
Sep. 30, 2013	Aug. 31, 2013 Revolving Line Of Credit Expires In July 2013	Aug. 31, 2013 Revolving Line Of Credit Expires In August 2015	Sep. 30, 2013 Loan Due May 2016
Commitments and Contingencies [Line Items]
Guarantee of affiliate's obligations		$ 24,000,000	$ 24,000,000
Line of credit maturity period			2015-08
Loan to affiliate	$ 3,402,000			$ 3,402,000
Loan to affiliate, due date				2016-05

The cash outflow from advancing money to an affiliate (an entity that is related but not strictly controlled by the entity).

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

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

-URI http://asc.fasb.org/extlink&oid=6516133

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (a)

-URI http://asc.fasb.org/extlink&oid=31042434&loc=d3e3213-108585

Name:	us-gaap_PaymentsForAdvanceToAffiliate
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration