Amounts Paid for Management Fee and Reimbursable Expenses (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Related Party Transaction [Line Items]
Management Fee	$ 4,522	$ 4,557	$ 13,956	$ 12,711
Reimbursable Expenses	701	407	1,869	1,033
Total Expenses	$ 5,223	$ 4,964	$ 15,825	$ 13,744

Cost associated with reimbursable income. This occurs when a services entity incurs expenses on behalf of the client and passes through the cost of reimbursable expenses to a client.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 225

-SubTopic 10

-Section S99

-Paragraph 2

-Subparagraph (SX 210.5-03.2)

-URI http://asc.fasb.org/extlink&oid=26872669&loc=d3e20235-122688

Name:	us-gaap_CostOfReimbursableExpense
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration