Fair Value of Financial Instruments (Details) - USD ($)	6 Months Ended	12 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Fair Value of Financial Instruments [Abstract]
Gross unrealized gains	$ 0	$ 0	$ 0
Gross unrealized losses	$ 0	$ 0	$ 0

Amount of unrealized gain on investment in debt security measured at fair value with change in fair value recognized in net income (trading).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 9
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=118939692&loc=d3e27357-111563

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