Condensed Financial Information (parent company only) - Balance Sheet (Details) (USD $)	Dec. 31, 2012	Dec. 31, 2011	Sep. 09, 2011	Dec. 31, 2010	Dec. 31, 2009
ASSETS
Cash			$ 25,813,171
Goodwill	141,375,000	141,357,000
Other assets	14,455,000	12,613,000
TOTAL ASSETS	4,304,821,000	4,173,076,000
LIABILITIES
Total Borrowings	367,089,000	489,374,000
Other Liabilities	37,272,000	31,655,000
Total Liabilities	3,752,585,000	3,658,609,000
Stockholders' Equity	552,236,000	514,467,000		454,408,000	463,785,000
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	4,304,821,000	4,173,076,000
Parent [Member]
ASSETS
Cash	35,160,000	20,654,000
Investments in Subsidiaries	633,971,000	611,809,000
Goodwill	448,000	448,000
Other assets	6,638,000	8,540,000
TOTAL ASSETS	676,217,000	641,451,000
LIABILITIES
Total Borrowings	111,702,000	115,826,000
Other Liabilities	12,279,000	11,158,000
Total Liabilities	123,981,000	126,984,000
Stockholders' Equity	552,236,000	514,467,000
TOTAL LIABILITIES AND STOCKHOLDERS' EQUITY	$ 676,217,000	$ 641,451,000