Parent Company Only Financial Information (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Dec. 31, 2012
Dec. 31, 2011
ASSETS        
Cash and due from subsidiary banks $ 339,438 $ 231,603    
Securities available for sale 759,065 841,310    
Investments in subsidiaries:        
Premises and equipment, net 63,974 65,827    
Other assets 41,288 43,562    
Total assets 3,665,607 3,539,575    
Liabilities:        
Junior subordinated debentures owed to unconsolidated Trusts 55,000 55,000    
Other liabilities 27,227 27,725    
Total liabilities 3,231,968 3,124,211    
Total stockholders' equity 433,639 415,364 408,797 409,267
Total liabilities and stockholders' equity 3,665,607 3,539,575    
Parent        
ASSETS        
Cash and due from subsidiary banks 84,537 42,645    
Securities available for sale 201 201    
Investments in subsidiaries:        
Bank 373,773 400,442    
Non-bank 28,348 25,646    
Premises and equipment, net 523 521    
Other assets 8,684 9,450    
Total assets 496,066 478,905    
Liabilities:        
Junior subordinated debentures owed to unconsolidated Trusts 55,000 55,000    
Other liabilities 7,427 8,541    
Total liabilities 62,427 63,541    
Total stockholders' equity 433,639 415,364    
Total liabilities and stockholders' equity $ 496,066 $ 478,905