BUSINESS COMBINATIONS (Details Textual)			1 Months Ended		12 Months Ended
		Jun. 12, 2015 USD ($)	May. 22, 2015 USD ($)	Jun. 30, 2014 USD ($) shares	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)
Goodwill, excess of the merger consideration over fair value of net assets					$ 90,082,000	$ 63,547,000	$ 35,049,000
Issuance of common stock, fair value					$ 0	34,474,000	$ 24,629,000
Coastal Bank share Inc [Member]
Goodwill, excess of the merger consideration over fair value of net assets						$ 28,093,000
Shares to receive for each share of Prosperity common stock pursuant to the merger agreement				0.4671
Issuance of common stock, shares | shares				1,598,998
Issuance of common stock, fair value				$ 34,500,000
Fair value of loans acquired				279,400,000
Net of loans acquired				$ 16,700,000
Estimated discount				5.64%
Accretable yield				$ 29,300,000
Coastal Bank share Inc [Member] | As Recorded by Acquired Bank [Member]
Goodwill, excess of the merger consideration over fair value of net assets				28,100,000
Coastal Bank share Inc [Member] | Warrant [Member]
Cash in exchange for outstanding warrants				$ 2,800,000
Merchants and Southern Banks of Florida [Member]
Number of banking locations			13
Goodwill, excess of the merger consideration over fair value of net assets			$ 0
Fair value of loans acquired			191,500,000
Net of loans acquired			$ 8,500,000
Estimated discount			4.25%
Accretable yield			$ 11,200,000
Payments to Acquire Businesses, Gross			50,000,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment			14,614,000
Purchase price			50,000,000
Merchants and Southern Banks of Florida [Member] | As Recorded by Acquired Bank [Member]
Goodwill, excess of the merger consideration over fair value of net assets	[1]		14,670,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment			$ 10,934,000
Bank Of America [Member]
Goodwill, excess of the merger consideration over fair value of net assets		$ 0
Fair value of loans acquired		4,000,000
Net of loans acquired		4,000,000
Accretable yield		$ 364,000
Number Of Bank Branches		18
Deposit Premium On Deposits Assumed		3.00%
Average Daily Deposits Period		15 days
Payments to Acquire Businesses, Gross		$ 20,000,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment		10,348,000
Purchase price		20,002,000
Bank Of America [Member] | As Recorded by Acquired Bank [Member]
Goodwill, excess of the merger consideration over fair value of net assets		11,210,000
Business Combination, Recognized Identifiable Assets Acquired and Liabilities Assumed, Property, Plant, and Equipment		$ 10,653,000

[1] Adjustment reflects the deferred taxes on the difference in the carrying values of acquired assets and assumed liabilities for financial reporting purposes and their basis for federal income tax purposes.