A device of credit enhancement where a part of the purchase price for the receivable/ payable is retained to serve as a cash collateral.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 5
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4332-108586

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4304-108586

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 4
-URI http://asc.fasb.org/extlink&oid=98513485&loc=d3e4313-108586

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

Discontinued operations - Additional Information (Details) - USD ($)		1 Months Ended		3 Months Ended		12 Months Ended
	Jan. 07, 2019	Aug. 31, 2019	Feb. 14, 2019	Dec. 31, 2018	Sep. 30, 2018	Dec. 31, 2017	Dec. 31, 2016
Discontinued operations
Proceeds From Repatriated Funds	$ 1,100,000			$ 1,000,000	$ 2,750,000	$ 458,000	$ 400,000
Disposal Group, Including Discontinued Operation, Consideration			$ 7,000,000
Proceeds from Divestiture of Businesses		$ 265,000	6,735,000
Supplemental Deferred Purchase Price			$ 265,000