Represents the expected term of the debt instrument.

No definition available.

Name:	ssd_DebtInstrumentTerm
Namespace Prefix:	ssd_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of additional borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed.

+ References

No definition available.

+ Details

Name:	ssd_LineOfCreditIncreaseInCurrentBorrowingCapacity
Namespace Prefix:	ssd_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Aggregate dividends paid during the period for each share of common stock outstanding.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Article 3

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 505

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.3-04)

-URI http://asc.fasb.org/extlink&oid=6959260&loc=d3e187085-122770

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Aggregate dividends declared during the period for each share of common stock outstanding.

+ References

+ Details

Name:	us-gaap_CommonStockDividendsPerShareDeclared
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage points added to the reference rate to compute the variable rate on the debt instrument.

+ References

No definition available.

+ Details

Name:	us-gaap_DebtInstrumentBasisSpreadOnVariableRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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

- Definition

Equity impact of common stock cash dividends declared by an entity during the period. This element includes paid and unpaid dividends declared during the period.

+ References

+ Details

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

- Definition

The fee, expressed as a percentage of the line of credit facility, for the line of credit facility regardless of whether the facility has been used.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of current borrowing capacity under the credit facility considering any current restrictions on the amount that could be borrowed (for example, borrowings may be limited by the amount of current assets), but without considering any amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Definition

Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Statement of Financial Accounting Standard (FAS)

-Number 129

-Paragraph 2, 4

-LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy.

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 19, 22

-Article 5

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.19(b),22(b))

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Details

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Period Type:	duration

Subsequent Events (Details) (USD $)	3 Months Ended		6 Months Ended			1 Months Ended				1 Months Ended					1 Months Ended
Subsequent Events (Details) (USD $)	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Dec. 31, 2011	Jun. 30, 2011	Oct. 31, 2012 Dividend declared, July 2012	Jul. 31, 2012 Dividend declared, July 2012	Jul. 31, 2012 Unsecured credit agreement	Jul. 27, 2012 Unsecured credit agreement	Jul. 31, 2012 Unsecured credit agreement LIBOR	Jul. 31, 2012 Unsecured credit agreement Base rate	Jul. 31, 2012 Unsecured credit agreement Maximum	Jul. 27, 2012 Unsecured credit agreement Maximum LIBOR	Jul. 27, 2012 Unsecured credit agreement Maximum Base rate	Jul. 31, 2012 Unsecured credit agreement Minimum	Jul. 27, 2012 Unsecured credit agreement Minimum LIBOR	Jul. 27, 2012 Unsecured credit agreement Minimum Base rate
Subsequent Events
Cash dividends declared per common share (in dollars per share)	$ 0.125	$ 0.125	$ 0.25	$ 0.25	$ 0.25		$ 0.125
Cash dividend declared			$ 12,081,000	$ 11,810,000	$ 12,526,000		$ 6,000,000
Cash dividends paid per common share (in dollars per share)						$ 0.125
Term of credit facility								5 years
Revolving credit facility current borrowing capacity									300,000,000
Increase in current borrowing capacity								200,000,000
Maximum borrowing capacity	$ 206,300,000		$ 206,300,000						$ 500,000,000
Credit agreement, annual facility fee (as a percent)												0.30%			0.15%
Interest rate basis (as a percent)										LIBOR	Base Rate
Interest rate spread (as a percent)													1.45%	0.45%		0.60%	0.00%