PARENT COMPANY STATEMENTS, Condensed Balance Sheets (Details) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Assets [Abstract]
Cash and cash equivalents	$ 153,210	$ 138,396	$ 149,647	$ 228,558
Other assets	170,129	140,912
Total assets	8,552,669	7,489,440	7,095,864
Liabilities and shareholders' equity [Abstract]
Accrued interest and other liabilities	135,102	126,150
Borrowings	102,146	102,122
Shareholders' equity	1,140,647	987,904	875,812	902,778
Total liabilities and shareholders' equity	8,552,669	7,489,440
Parent Company [Member]
Assets [Abstract]
Cash and cash equivalents	97,317	106,957	$ 83,783	$ 43,800
Investment securities	3,576	3,622
Investment in and advances to subsidiaries	1,148,062	984,561
Other assets	9,996	9,608
Total assets	1,258,951	1,104,748
Liabilities and shareholders' equity [Abstract]
Accrued interest and other liabilities	16,158	14,722
Borrowings	102,146	102,122
Shareholders' equity	1,140,647	987,904
Total liabilities and shareholders' equity	$ 1,258,951	$ 1,104,748