Earnings Per Common Share (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended	9 Months Ended
Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Earnings Per Common Share
Number of shares awarded under Pay-for-Performance program included in diluted weighted average number of shares	100,000	100,000	100,000	100,000
Underlying number of shares awarded under Pay-for-Performance program included in calculation of diluted weighted average number of shares	200,000	200,000	200,000	200,000
Number of shares awarded under Pay-for-Performance program not included in diluted weighted average number of shares	100,000	100,000	100,000	100,000
Outstanding options at the end of the period (in shares)	0	0	0	0
Numerator for basic and diluted earnings per share:
Income from continuing operations	$ 3,228	$ 3,001	$ 14,429	$ 9,228
Less net income attributable to noncontrolling interests	(17)	(6)	(32)	(13)
Less earnings allocated to unvested shares	(165)		(494)
Income from continuing operations available for common stockholders	3,046	2,995	13,903	9,215
Discontinued operations		15,419		18,171
Net income available for common stockholders, basic	3,046	18,414	13,903	27,386
Net income available for common stockholders, diluted	3,046	18,414	13,903	27,386
Denominator for basic earnings per share:
Weighted average common shares	15,093,000	14,443,000	14,871,000	14,370,000
Weighted average unvested restricted stock shares		408,000		412,000
Denominator for basic earnings per share (in shares)	15,093,000	14,851,000	14,871,000	14,782,000
Effect of diluted securities:
Restricted stock units awarded under Pay-for-Performance program (in shares)	100,000	100,000	100,000	100,000
Denominator for diluted earnings per share - weighted average shares	15,193,000	14,951,000	14,971,000	14,882,000
Earnings per common share, basic (in dollars per share)	$ 0.20	$ 1.24	$ 0.93	$ 1.85
Earnings per common share, diluted (in dollars per share)	$ 0.20	$ 1.23	$ 0.93	$ 1.84
Amounts attributable to One Liberty Properties, Inc. common stockholders, net of noncontrolling interests:
Income from continuing operations	3,211	2,995	14,397	9,215
Income from discontinued operations		15,419		18,171
Net income attributable to One Liberty Properties, Inc.	$ 3,211	$ 18,414	$ 14,397	$ 27,386

Represents the underlying number of shares from which is derived the additional shares to be included in the calculation of diluted EPS as a result of the potentially dilutive effect of share based payment arrangements using the treasury stock method.

No definition available.