Shareholders' Equity (Details) (USD $) In Thousands, except Share data, unless otherwise specified	0 Months Ended	3 Months Ended			3 Months Ended					3 Months Ended
	Dec. 11, 2012	Mar. 31, 2013 item	Dec. 31, 2012	Mar. 31, 2012	Mar. 31, 2013 Minimum [Member] item	Mar. 31, 2013 Maximum [Member] item	Mar. 31, 2013 Series B Preferred Stock [Member]	Dec. 31, 2012 Series B Preferred Stock [Member]	Aug. 18, 2011 Series B Preferred Stock [Member]	Mar. 31, 2013 More Than Four And One Half Years After Issuance [Member]	Mar. 31, 2013 Tenth Quarter Through Four And One Half Years After Issuance [Member] Minimum [Member]	Mar. 31, 2013 Tenth Quarter Through Four And One Half Years After Issuance [Member] Maximum [Member]	Mar. 31, 2013 Second Quarter Through Ninth Quarter After Issuance [Member] Minimum [Member]	Mar. 31, 2013 Second Quarter Through Ninth Quarter After Issuance [Member] Maximum [Member]
Class of Stock [Line Items]
Aggregate purchase price of preferred stock sold to treasury		$ 25,000	$ 25,000						$ 25,000
Stock sold to the treasury, shares							25,000	25,000	25,000
Liquidation value		$ 1,000	$ 1,000						$ 1,000
Par value of preferred stock		$ 2.5	$ 2.5						$ 2.50
Initial dividend percent									5.00%
Preferred stock, dividend rate (variable)													1.00%	5.00%
Preferred stock, dividend rate (fixed)										9.00%	1.00%	7.00%
Quarterly lending incentive fee										0.50%
Annual dividend rate		1.00%	1.00%	3.00%
Quarter Range, dividend adjusted					2	9
Number of quarters the dividend rate can fluctuate		30 months
Number of quarters after issuance rate is fixed in range		10
Number of years after issuance rate is fixed		4 years 6 months
Number of shares of common stock that may be issued		15,000,000	15,000,000
Common stock dividend distribution date	Dec. 11, 2012
Common stock dividends, shares percentage	5.00%
Common stock stock dividend, shares	211,564