Parent Company Only Financial Information (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
ASSETS
Cash and due from subsidiary banks	$ 351,255	$ 315,053
Securities available for sale	1,001,497	831,749
Loans	1,985,095	1,977,589
Investments in subsidiaries:
Premises and equipment, net	71,067	69,398
Other assets	53,442	61,810
Total assets	3,618,056	3,402,122
Liabilities:
Junior subordinated debt owed to unconsolidated trusts	55,000	55,000
Other liabilities	27,943	27,117
Total liabilities	3,209,259	2,992,855
Total stockholders' equity	408,797	409,267	420,505	328,128
Total liabilities and stockholders' equity	3,618,056	3,402,122
Parent
ASSETS
Cash and due from subsidiary banks	5,152	25,771
Securities available for sale	201	208
Loans	68	163
Investments in subsidiaries:
Bank	432,912	412,425
Non-bank	23,605	22,714
Premises and equipment, net	757	844
Other assets	9,369	9,487
Total assets	472,064	471,612
Liabilities:
Long-term ESOP debt		417
Junior subordinated debt owed to unconsolidated trusts	55,000	55,000
Other liabilities	8,267	6,928
Total liabilities	63,267	62,345
Total stockholders' equity	408,797	409,267
Total liabilities and stockholders' equity	$ 472,064	$ 471,612