Represents the carrying value as of the balance sheet date of payments made in excess of existing available balances.

No definition available.

Name:	sp_BookOverdrafts
Namespace Prefix:	sp_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Element represents the number of ownership interest entities.

+ References

No definition available.

+ Details

Name:	sp_NumberOfOwnershipInterestEntities
Namespace Prefix:	sp_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

No definition available.

+ Details

Name:	sp_VotingInterestOwnershipPercentage
Namespace Prefix:	sp_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

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

No definition available.

+ Details

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- Definition

This item represents the entity's proportionate share for the period of the net income (loss) of its investee (such as unconsolidated subsidiaries and joint ventures) to which the equity method of accounting is applied. This item includes income or expense related to stock-based compensation based on the investor's grant of stock to employees of an equity method investee.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 28

-Subparagraph (b)

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

-Publisher FASB

-Name Accounting Standards Codification

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-Section 45

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

-Publisher FASB

-Name Accounting Standards Codification

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-Section S99

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-Publisher SEC

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Reference 5: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 04

-Paragraph 11

-Article 7

+ Details

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

- Definition

The carrying amounts of cash and cash equivalent items which are restricted as to withdrawal or usage. Restrictions may include legally restricted deposits held as compensating balances against borrowing arrangements, contracts entered into with others, or entity statements of intention with regard to particular deposits; however, time deposits and short-term certificates of deposit are not generally included in legally restricted deposits. Excludes compensating balance arrangements that are not agreements which legally restrict the use of cash amounts shown on the balance sheet. This element is for unclassified presentations; for classified presentations there is a separate and distinct element.

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.1)

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

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

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 1

-Article 5

+ Details

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

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

- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

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

-Publisher FASB

-Name Accounting Standards Codification

-Topic 810

-SubTopic 10

-Section 50

-Paragraph 5A

-Subparagraph (d)

-URI http://asc.fasb.org/extlink&oid=28200181&loc=SL6759159-111685

+ Details

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

- Details

Name:	us-gaap_RangeAxis=us-gaap_MinimumMember
Namespace Prefix:
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Balance Type:
Period Type:

- Details

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Namespace Prefix:
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- Details

Name:	dei_LegalEntityAxis=sp_VariableInterestEntityMember
Namespace Prefix:
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Period Type:

- Details

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Namespace Prefix:
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Significant Accounting Policies and Practices (Details) $ in Thousands	1 Months Ended	3 Months Ended		6 Months Ended
	Oct. 31, 2014	Jun. 30, 2015 USD ($)	Jun. 30, 2014 USD ($)	Jun. 30, 2015 USD ($) item	Jun. 30, 2014 USD ($)	Dec. 31, 2014 USD ($)
Significant Accounting Policies and Practices
Ownership percentage	30.00%
Restricted Cash and Cash Equivalents \| $		$ 748		$ 748		$ 465
Financial Instruments
Book overdrafts \| $		26,920		$ 26,920		$ 30,782
Equity investment in unconsolidated subsidiaries.
Number of ownership interest entities				45
Equity earnings in related investments \| $		$ 526	$ 531	$ 930	$ 981
Minimum
Equity investment in unconsolidated subsidiaries.
Voting interest ownership percentage		30.00%		30.00%
Maximum
Equity investment in unconsolidated subsidiaries.
Voting interest ownership percentage		50.00%		50.00%
VIEs
Equity investment in unconsolidated subsidiaries.
Number of ownership interest entities				29
Voting interest model entities
Equity investment in unconsolidated subsidiaries.
Number of ownership interest entities				17