Fair Value - Quantitative Disclosure for Assets Classified as Level 3 (Detail) - Common Stock at Fair Value $ in Thousands	3 Months Ended
Mar. 31, 2016 USD ($)
Fair Value, Assets Measured on Recurring and Nonrecurring Basis [Line Items]
Balance at December 31, 2015	$ 3,276
Investments and capital calls	207
Balance at March 31, 2016	$ 3,483

Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=36462937&loc=d3e19207-110258

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