Nature of Operations and Summary of Significant Accounting Policies (Details) (USD $)	Jun. 30, 2013	Dec. 31, 2012
Assets
Loans receivable	$ 3,673,456,000	$ 3,397,425,000
Premises and equipment, net	161,918,000	158,989,000
Accrued interest receivable	43,593,000	37,770,000
Other assets	47,053,000	41,969,000
Total assets	7,996,816,000	7,747,440,000
Liabilities
Other borrowed funds	8,489,000	10,032,000
Accrued interest payable	3,824,000	4,675,000
Other liabilities	54,345,000	55,384,000
Total liabilities	7,067,814,000	6,846,491,000
CDE (NMTC) [Member]
Assets
Loans receivable	35,840,000	35,480,000
Accrued interest receivable	113,000	117,000
Other assets	969,000	1,114,000
Total assets	36,922,000	36,711,000
Liabilities
Other borrowed funds	4,555,000	4,555,000
Accrued interest payable	4,000	4,000
Other liabilities	92,000	182,000
Total liabilities	4,651,000	4,741,000
LIHTC [Member]
Assets
Premises and equipment, net	13,745,000	16,066,000
Other assets	153,000	143,000
Total assets	13,898,000	16,209,000
Liabilities
Other borrowed funds	1,722,000	3,639,000
Accrued interest payable	5,000	6,000
Other liabilities	177,000	136,000
Total liabilities	$ 1,904,000	$ 3,781,000