Name:	syn_BusinessCombinationAcquiredReceivableFairValueEffectivelySettled
Namespace Prefix:	syn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

No definition available.

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Amount of consideration transferred, consisting of acquisition-date fair value of assets transferred by the acquirer, liabilities incurred by the acquirer, and equity interest issued by the acquirer.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 30
-Paragraph 8
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-SubTopic 30
-Section 50
-Paragraph 1
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Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
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-Section 30
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Name:	us-gaap_BusinessCombinationConsiderationTransferred1
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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

Amount of equity interests of the acquirer, including instruments or interests issued or issuable in consideration for the business combination.

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

This element represents the amount of any change recognized during the period in the low-end of the estimated range of outcomes (undiscounted) of a liability assumed in a business combination arising from an item of contingent consideration.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
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-SubTopic 30
-Section 50
-Paragraph 4
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-URI https://asc.fasb.org/extlink&oid=126975305&loc=d3e7008-128479

Name:	us-gaap_BusinessCombinationContingentConsiderationArrangementsChangeInTheRangeOfOutcomesContingentConsiderationLiabilityValueLow
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Data Type:	xbrli:monetaryItemType
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Period Type:	duration

Amount of liability recognized arising from contingent consideration in a business combination.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 50
-Paragraph 1
-Subparagraph (c)(1)
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-Name Accounting Standards Codification
-Topic 805
-SubTopic 30
-Section 25
-Paragraph 6
-URI https://asc.fasb.org/extlink&oid=6911189&loc=d3e6408-128476

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

The cash outflow associated with the acquisition of business during the period. The cash portion only of the acquisition price.