Related Party Transactions (Narrative) (Details) $ in Thousands	3 Months Ended
Mar. 31, 2016 USD ($)
Related Party Transaction [Line Items]
Payments for repurchase of common stock	$ 6,032
CAIJ [Member]
Related Party Transaction [Line Items]
Ownership percentage by parent	80.00%
Ownership percentage by noncontrolling interest	20.00%

The equity interest of noncontrolling shareholders, partners or other equity holders in consolidated entity.

No definition available.

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Namespace Prefix:	us-gaap_
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- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

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- Definition

The cash outflow to reacquire common stock during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=66902209&loc=d3e3291-108585

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Glossary Financing Activities
-URI http://asc.fasb.org/extlink&oid=6513228

+ Details

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Balance Type:	credit
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- 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

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Balance Type:	na
Period Type:	duration

- Details

Name:	dei_LegalEntityAxis=cap_CaijMember
Namespace Prefix:
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Balance Type:
Period Type: