XML 87 R72.htm IDEA: XBRL DOCUMENT
v3.8.0.1

Note 12 - Share-based Compensation - Summary of Significant Assumptions for Share-based Compensation Awards (Details) - $ / shares | 12 Months Ended
--- | ---
Dec. 31, 2017 | Dec. 31, 2016 | Dec. 31, 2015
Risk free interest rate |  |  |  |  |  |
Expected award (Year) |  | 5 years |  |  |  |
Stock Appreciation Rights (SARs) [Member] |  |  |  |  |  |
Exercise price |  |  |  |  |  |
Exercise price (in dollars per share) |  | $ 16.97 | $ 16.35 |  | $ 18.66 |
Market price |  |  |  |  |  |
Market price (in dollars per share) |  | $ 16.97 | $ 16.35 |  | $ 18.66 |
Risk free interest rate |  |  |  |  |  |
Risk free interest rate | [1] | 1.90% | 1.30% |  | 1.50% |
Expected award (Year) | [2] | 5 years |  |  |  |
Expected volatility |  |  |  |  |  |
Expected volatility | [3] | 36.60% | 36.50% |  | 34.90% |
Expected dividend yield |  |  |  |  |  |
Expected dividend yield | [4] | 2.10% | 2.00% |  | 1.60% |
Employee Stock Option [Member] | Minimum [Member] |  |  |  |  |  |
Exercise price |  |  |  |  |  |
Exercise price (in dollars per share) |  | $ 16.97 | $ 16.35 |  | $ 16.78 |
Market price |  |  |  |  |  |
Market price (in dollars per share) |  | $ 16.97 | $ 16.35 |  | $ 16.78 |
Risk free interest rate |  |  |  |  |  |
Risk free interest rate |  | 1.80% | 1.10% | [1] | 1.50% | [1]
Expected award (Year) | [2] | 5 years |  |  |  |
Expected volatility |  |  |  |  |  |
Expected volatility | [3] | 36.60% | 36.50% |  | 34.90% |
Expected dividend yield |  |  |  |  |  |
Expected dividend yield | [4] | 1.80% | 1.80% |  | 1.60% |
Employee Stock Option [Member] | Maximum [Member] |  |  |  |  |  |
Exercise price |  |  |  |  |  |
Exercise price (in dollars per share) |  | $ 21.63 | $ 18.55 |  | $ 18.66 |
Market price |  |  |  |  |  |
Market price (in dollars per share) |  | $ 21.63 | $ 18.55 |  | $ 18.66 |
Risk free interest rate |  |  |  |  |  |
Risk free interest rate | [1] | 2.40% | 1.80% |  | 2.10% |
Expected award (Year) | [2] | 10 years |  |  |  |
Expected volatility |  |  |  |  |  |
Expected volatility | [3] | 41.40% | 40.30% |  | 39.00% |
Expected dividend yield |  |  |  |  |  |
Expected dividend yield | [4] | 2.10% | 2.10% |  | 1.90% |
[1] | The risk-free interest rate is based on the yield of a U.S. treasury bond with a similar maturity as the expected life of the awards.
[2] | The expected life in years for awards granted was based on the historical exercise patterns experienced by the Company when the award is made.
[3] | The determination of expected stock price volatility for awards granted in each of the three years ended December 31, 2017, 2016 and 2015 was based on historical Superior common stock prices over a period commensurate with the expected life.
[4] | The dividend yield assumption is based on the history and expectation of the Company's dividend payouts.

X
- Definition Exercise price [abstract] + References No definition available. + Details
Name: | sgc_ExercisePriceAbstract
Namespace Prefix: | sgc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Expected dividend yield [abstract] + References No definition available. + Details
Name: | sgc_ExpectedDividendYieldAbstract
Namespace Prefix: | sgc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Expected volatility [abstract] + References No definition available. + Details
Name: | sgc_ExpectedVolatilityAbstract
Namespace Prefix: | sgc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Represents the market price. + References No definition available. + Details
Name: | sgc_MarketPrice
Namespace Prefix: | sgc_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | duration

X
- Definition Marketprice [abstract] + References No definition available. + Details
Name: | sgc_MarketPriceAbstract
Namespace Prefix: | sgc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Risk free interest rate [abstract] + References No definition available. + Details
Name: | sgc_RiskFreeInterestRate1Abstract
Namespace Prefix: | sgc_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Agreed-upon price for the exchange of the underlying asset relating to the share-based payment award. + References No definition available. + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExercisePrice
Namespace Prefix: | us-gaap_
Data Type: | num:perShareItemType
Balance Type: | na
Period Type: | instant

X
- Definition The estimated dividend rate (a percentage of the share price) to be paid (expected dividends) to holders of the underlying shares over the option's term. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(iii) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedDividendRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The estimated measure of the percentage by which a share price is expected to fluctuate during a period. Volatility also may be defined as a probability-weighted measure of the dispersion of returns about the mean. The volatility of a share price is the standard deviation of the continuously compounded rates of return on the share over a specified period. That is the same as the standard deviation of the differences in the natural logarithms of the stock prices plus dividends, if any, over the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(ii) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsExpectedVolatilityRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition The risk-free interest rate assumption that is used in valuing an option on its own shares. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(iv) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 + Details
Name: | us-gaap_ShareBasedCompensationArrangementByShareBasedPaymentAwardFairValueAssumptionsRiskFreeInterestRate
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | duration

X
- Definition Expected term of share-based compensation awards, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph (f)(2)(i) -URI http://asc.fasb.org/extlink&oid=96867065&loc=d3e5070-113901 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 718 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SAB Topic 14.D.2) -URI http://asc.fasb.org/extlink&oid=27013229&loc=d3e301413-122809 + Details
Name: | us-gaap_SharebasedCompensationArrangementBySharebasedPaymentAwardFairValueAssumptionsExpectedTerm1
Namespace Prefix: | us-gaap_
Data Type: | xbrli:durationItemType
Balance Type: | na
Period Type: | duration

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_StockAppreciationRightsSARSMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_AwardTypeAxis=us-gaap_EmployeeStockOptionMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |

X
- Details
Name: | us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix: |
Data Type: | na
Balance Type: |
Period Type: |