Basis of Presentation and Summary of Significant Accounting Policies - Additional Information (Detail) - USD ($)	3 Months Ended
Mar. 31, 2017	Dec. 31, 2016
Accounting Policies [Abstract]
Restricted cash	$ 12,340,952	$ 11,918,100
Cash denominated in foreign currencies	351	992,914
Cash denominated in foreign currencies, proceeds	$ 2,334	$ 1,024,772
Income tax examination, description	No income tax returns are currently under examination. The 2013 through 2016 tax years remain subject to examination by U.S. federal and most state tax authorities.

The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02.1)
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

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