COMPREHENSIVE INCOME (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
COMPREHENSIVE INCOME [Abstract]
Net income	$ 37,199us-gaap_NetIncomeLoss	$ 12,727us-gaap_NetIncomeLoss	$ 4,313us-gaap_NetIncomeLoss
Change in net unrealized gains on investments available for sale	2,856	3,041	5,114
Comprehensive income before tax	40,055	15,768	9,427
Income tax expense related to items of other comprehensive income	(1,102)	(1,144)	(1,924)
Comprehensive income	$ 38,953us-gaap_ComprehensiveIncomeNetOfTax	$ 14,624us-gaap_ComprehensiveIncomeNetOfTax	$ 7,503us-gaap_ComprehensiveIncomeNetOfTax

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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

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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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Amount before tax of other comprehensive income (loss) attributable to parent entity.

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Amount before tax and reclassification adjustments of unrealized holding gain (loss) on available-for-sale securities.

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Amount of tax expense (benefit) before reclassification adjustments of unrealized holding gain (loss) on available-for-sale securities.

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