Agreements and Transactions with Related Parties (Details 2) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Due to Affiliate
Deferred acquisition fees, including interest	$ 17,525cpa18_OfferingAndOfferingCostsUnpaid	$ 2,705cpa18_OfferingAndOfferingCostsUnpaid
Accounts payable	2,702	2,406
Asset management fees payable	378	38
Reimbursable costs	46cpa18_DueToAffiliateOther	0cpa18_DueToAffiliateOther
Due to affiliates	$ 20,651	$ 5,149

Carrying amount as of the balance sheet date of obligations due all related parties.

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

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

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Reference 4: http://www.xbrl.org/2003/role/presentationRef

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

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Reference 6: http://www.xbrl.org/2003/role/presentationRef

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