XML 60 R49.htm IDEA: XBRL DOCUMENT
v3.21.2

Treasury Stock - Additional Information (Details) - USD ($) | 9 Months Ended |
--- | --- | ---
Sep. 30, 2021 | Oct. 17, 2016
Equity, Class of Treasury Stock [Line Items] |  |
Treasury stock (in shares) | 64,702,267 |
2016 BOD Authorized Common Stock Repurchase |  |
Equity, Class of Treasury Stock [Line Items] |  |
Stock repurchase program, additional repurchase authorization |  | $ 300,000,000.0
Remaining authorized repurchase amount | $ 76,600,000 |
2004 Amended and Restated Stock Incentive Plan |  |
Equity, Class of Treasury Stock [Line Items] |  |
Treasury shares issued for restricted stock units that vested during the period (in shares) | 576,232 |
Average cost of treasury shares that were issued for restricted stock units that vested during the period (usd per share) | $ 3.19 |
Shares repurchased to satisfy minimum employee withholding tax requirements resulting from the vesting of such restricted stock units (in shares) | 223,030 |
Average cost per share of treasury stock acquired (usd per share) | $ 38.44 |

X
- Definition Treasury stock issued during period, average cost per share, restricted stock units + References No definition available. + Details
Name: | slgn_Treasurystockissuedduringperiodaveragecostpershare
Namespace Prefix: | slgn_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition 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. + References No definition available. + Details
Name: | us-gaap_EquityClassOfTreasuryStockLineItems
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of shares issued under share-based payment arrangement. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=120381028&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardSharesIssuedInPeriod
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of shares used to settle grantee's tax withholding obligation for award under share-based payment arrangement. + References No definition available. + Details
Name: | us-gaap_SharesPaidForTaxWithholdingForShareBasedCompensation
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | duration

X
- Definition Amount of stock repurchase plan authorized. + References No definition available. + Details
Name: | us-gaap_StockRepurchaseProgramAuthorizedAmount1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Amount remaining of a stock repurchase plan authorized. + References No definition available. + Details
Name: | us-gaap_StockRepurchaseProgramRemainingAuthorizedRepurchaseAmount1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Total cost of shares repurchased divided by the total number of shares repurchased. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655 + Details
Name: | us-gaap_TreasuryStockAcquiredAverageCostPerShare
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Number of common and preferred shares that were previously issued and that were repurchased by the issuing entity and held in treasury on the financial statement date. This stock has no voting rights and receives no dividends. + References Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.29,30) -URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682 Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef -Publisher FASB -Name Accounting Standards Codification -Topic 505 -SubTopic 30 -Section 45 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655 + Details
Name: | us-gaap_TreasuryStockShares
Namespace Prefix: | us-gaap_
Data Type: | xbrli:sharesItemType
Balance Type: | na
Period Type: | instant

X
- Details
Name: | us-gaap_ShareRepurchaseProgramAxis=slgn_A2016BODAuthorizedCommonStockRepurchaseMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | slgn_TreasuryStockAxis=slgn_ActivityrelatedtorestrictedstockunitsvestedundertheAmendedandRestated2004StockIncentivePlanMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |