CONDENSED FINANCIAL INFORMATION OF PARENT COMPANY (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Assets:
Cash and due from banks	$ 96,424	$ 89,011
Other assets	199,663	112,107
Total assets	6,533,363	5,463,658
Liabilities:
Subordinated debentures	132,645	108,250
Other liabilities	73,884	44,575
Total liabilities	5,724,270	4,874,537
Stockholders' equity	809,093	589,121	546,203	478,797
Total liabilities and stockholders' equity	6,533,363	5,463,658
Parent company
Assets:
Cash and due from banks	21,835	28,472
Investments in subsidiaries	911,200	649,656
Other assets	10,341	20,174
Total assets	943,376	698,302
Liabilities:
Subordinated debentures	132,645	108,250
Other liabilities	1,638	931
Total liabilities	134,283	109,181
Stockholders' equity	809,093	589,121
Total liabilities and stockholders' equity	$ 943,376	$ 698,302