MERGERS AND ACQUISITIONS - Narrative (Details) - USD ($) $ / shares in Units, $ in Thousands	Jul. 20, 2016	Mar. 01, 2016	Dec. 31, 2016	Dec. 31, 2015
Common stock, par value (in dollars per share)			$ 1.00	$ 1.00
F.N.B. Corporation
Stock exchange ratio (in shares)	2.16
Common stock, par value (in dollars per share)	$ 0.01
Business acquisition, share price (in dollars per share)	$ 13.20
Total purchase price	$ 1,470,000
NewBridge Bancorp
Stock exchange ratio (in shares)		0.50
Total purchase price		$ 431,336