PARENT ONLY CONDENSED FINANCIAL STATEMENTS (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Assets
Cash and cash equivalents	$ 65,650	$ 109,148	$ 60,123	$ 71,689
Securities available for sale	902,341	876,090
Total assets	2,769,288	2,754,180
Liabilities
Subordinated debentures	50,418	50,267
Other liabilities	34,494	30,244
Total liabilities	2,445,537	2,417,627
Shareholders' equity	323,751	336,553	302,570	294,462
Total liabilities and shareholders' equity	2,769,288	2,754,180
Parent Company
Assets
Cash and cash equivalents	7,102	8,022	14,284	20,924
Securities available for sale	399	899
Investment in subsidiaries	361,397	372,476
Other assets	11,523	11,482
Total assets	380,421	392,879
Liabilities
Subordinated debentures	50,418	50,267
Other liabilities	6,252	6,059
Total liabilities	56,670	56,326
Shareholders' equity	323,751	336,553
Total liabilities and shareholders' equity	$ 380,421	$ 392,879