Basis of Accounting and Consolidation (Details) (USD $)	1 Months Ended	2 Months Ended	3 Months Ended		4 Months Ended	6 Months Ended			12 Months Ended		6 Months Ended	12 Months Ended	6 Months Ended	9 Months Ended	12 Months Ended	1 Months Ended	6 Months Ended	12 Months Ended				6 Months Ended
	Feb. 11, 2011	Mar. 02, 2011	Jun. 30, 2012	Jun. 30, 2011	May 13, 2011	Jun. 28, 2012	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Dec. 31, 2009	Jun. 30, 2012 Accumulated Other Comprehensive Income (Loss) [Member]	Dec. 31, 2011 Accumulated Other Comprehensive Income (Loss) [Member]	Jun. 30, 2012 Series B Convertible Preferred Stock [Member]	Sep. 30, 2008 Series B Convertible Preferred Stock [Member]	Dec. 31, 2009 Series B Convertible Preferred Stock [Member]	Feb. 11, 2011 Series C Convertible Preferred Stock [Member]	Jun. 30, 2012 Series C Convertible Preferred Stock [Member]	Dec. 31, 2010 Series C Convertible Preferred Stock [Member]	Jun. 30, 2011 Series C Convertible Preferred Stock [Member]	May 13, 2011 Series C Convertible Preferred Stock [Member]	Mar. 02, 2011 Series C Convertible Preferred Stock [Member]	Jun. 30, 2012 Stock Options [Member]	Jun. 30, 2012 Stock Unit Awards and Stock Awards [Member]	Jun. 30, 2012 Stock Awards [Member]	Jun. 30, 2012 Stock Unit Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Maximum number of shares to be issued in stock incentive plan (in shares)			300,000				300,000
Common stock awarded in SI plan (in shares)																						59,500	17,409
Percentage of Awards Issued (in hundredths)																								50.00%	50.00%
Series B Convertible Preferred Stock [Abstract]
Preferred stock issue price (in dollars per share)															$ 5,000		$ 5,000
Number of dividend periods															4	4
Number of Directors to be Elected by Holders of Preferred Stock															2	2
Liquidation preference per share (in dollars per share)															$ 5,000		$ 5,000
Preferred stock, conversion price per share (in dollars per share)															$ 21.94		$ 20.29
Preferred stock, redemption price per share (in dollars per share)															$ 5,000				$ 5,000
Percentage of common stock book value requiring the conversion of preferred stock (in hundredths)														115.00%
Common Stock, Book Value (in dollars per share)													$ 16.89	$ 13.03
115% of common stock book value (in dollars per share)														$ 14.98
Preferred stock, revised conversion price per share (in dollars per share)													$ 21.62
Proceeds from Issuance of Convertible Preferred Stock	11,010,000	2,750,000			5,490,000	8,250,000	27,500,000			24,635,000
Preferred Stock, Dividend Rate, Percentage (in hundredths)	8.00%									9.00%
Series C Convertible Preferred Stock [Abstract]
Preferred Stock, shares subscribed, value	27,500,000
Number of Investors Completing the Required Bank Regulatory Process																				4	3
Preferred Stock issued during period, value			52,035,000				52,035,000		43,785,000
Percentage of common stock tangible book value requiring the conversion of common stock (in hundredths)																		115.00%
Tangible book value per share of common stock (in dollars per share)																	$ 12.04	$ 9.38
115% of common stock tangible book value (in dollars per share)																		$ 10.79
Percentage of the NASDAQ Bank Index requiring the conversion of Series C Preferred Stock (in hundredths)																		115.00%
NASDAQ Bank Index																	1,785.51	1,847.35
115% of NASDAQ Bank Index																		2,124.45
Proceeds from Issuance of Convertible Preferred Stock	11,010,000	2,750,000			5,490,000	8,250,000	27,500,000			24,635,000
Preferred Stock, Dividend Rate, Percentage (in hundredths)	8.00%									9.00%
Other Comprehensive Income:
Tax expense							2,421,000		2,012,000
Comprehensive income			4,093,000	5,897,000			7,511,000	9,487,000
Accumulated Other Comprehensive Income (Loss), Net of Tax [Abstract]
Net unrealized gains on securities available-for-sale											10,935,000	10,066,000
Unrealized gain (loss) on available-for-sale securities, tax benefit											(4,262,000)	(3,924,000)
Total unrealized gain (loss) on available for sale securities, net of tax											6,673,000	6,142,000
Securities with other-than-temporary impairment losses											(4,724,000)	(4,906,000)
Securities with other-than-temporary impairment losses, tax benefit											1,841,000	1,912,000
Total securities with other-than-temporary impairment losses, net of tax											(2,883,000)	(2,994,000)
Accumulated other comprehensive income, tax							(2,421,000)		(2,012,000)
Total accumulated other comprehensive income, net of tax											$ 3,790,000	$ 3,148,000