Leases - Summary of Selected Financial Data (Detail) (USD $) In Thousands, unless otherwise specified	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Condensed Financial Statements, Captions [Line Items]
Total revenue	$ 23,920us-gaap_RealEstateRevenueNet	$ 23,757us-gaap_RealEstateRevenueNet
Operating income	2,535us-gaap_OperatingIncomeLoss	10,141us-gaap_OperatingIncomeLoss
Net income (loss)	(1,137)us-gaap_NetIncomeLoss	9,638us-gaap_NetIncomeLoss
CPD NY and NECG [Member]
Condensed Financial Statements, Captions [Line Items]
Total revenue	90,491	127,167
Gross profit	7,415	9,261
Net income (loss)	902	11
Current assets	15,167		13,520
Noncurrent assets	29,887		28,995
Current liabilities	3,416		2,531
Noncurrent liabilities	28,957		28,204
White Oak Petroleum, LLC, Hudson Petroleum Realty, LLC, Dogwood Petroleum Realty, LLC and Big Apple Petroleum Realty, LLC [Member]
Condensed Financial Statements, Captions [Line Items]
Total revenue	59,473	84,249
Operating income	2,630	1,233
Net income (loss)	(633)	(1,995)
Current assets	4,459		9,288
Noncurrent assets	107,474		108,491
Current liabilities	8,501		13,793
Noncurrent liabilities	$ 134,794		$ 134,700

Sum of the carrying amounts as of the balance sheet date of all assets that are expected to be realized in cash, sold, or consumed within one year (or the normal operating cycle, if longer). Assets are probable future economic benefits obtained or controlled by an entity as a result of past transactions or events.

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Sum of the carrying amounts as of the balance sheet date of all assets that are expected to be realized in cash, sold or consumed after one year or beyond the normal operating cycle, if longer.

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Aggregate revenue less cost of goods and services sold or operating expenses directly attributable to the revenue generation activity.

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Total obligations incurred as part of normal operations that are expected to be paid during the following twelve months or within one business cycle, if longer.

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Amount of obligation due after one year or beyond the normal operating cycle, if longer.

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The portion of profit or loss for the period, net of income taxes, which is attributable to the parent.

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The aggregate revenue from real estate operations during the reporting period.

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