Other Long-Term Assets - Additional Information (Detail) (USD $)	12 Months Ended
Dec. 31, 2013
Maximum [Member]
Other Long Term Assets [Line Items]
Number of years for Image use rights	5 years
Marine equipment deposits	$ 1,187,400
United Kingdom's Ministry of Defense [Member]
Other Long Term Assets [Line Items]
Deposits with United Kingdom's Ministry of Defense	432,500
Conservation and Documentation of Artifacts [Member]
Other Long Term Assets [Line Items]
Deposits for conservation and documentation of artifacts	$ 100,000

The aggregate of all deposit liabilities held by the entity, including foreign and domestic, interest and noninterest bearing; may include demand deposits, saving deposits, Negotiable Order of Withdrawal (NOW) and time deposits among others.

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.12)

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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 12

-Article 9

Name:	us-gaap_Deposits
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant