EARNINGS PER SHARE - Earnings per share attributable to common stock and restricted shares (Details 1) (USD $)	3 Months Ended
Mar. 31, 2015	Mar. 31, 2014
Earnings Per Share [Line Items]
Basic (in dollars per share)	$ 0.04us-gaap_EarningsPerShareBasic	$ 0.18us-gaap_EarningsPerShareBasic
Common Stock
Earnings Per Share [Line Items]
Basic (in dollars per share)	$ 0.04	$ 0.18
Restricted Shares
Earnings Per Share [Line Items]
Basic (in dollars per share)	$ 0.02	$ 0.16

The amount of net income (loss) for the period per each share of common stock or unit outstanding during the reporting period.

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Name:	us-gaap_EarningsPerShareBasic
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration