Shareholders' Equity (Details) - Dividend Transactions (USD $) In Thousands, except Per Share data, unless otherwise specified	0 Months Ended												3 Months Ended		6 Months Ended		0 Months Ended												6 Months Ended		0 Months Ended												6 Months Ended
	Jun. 27, 2014	Jun. 16, 2014	May 29, 2014	May 15, 2014	Apr. 29, 2014	Apr. 15, 2014	Mar. 28, 2014	Mar. 17, 2014	Feb. 27, 2014	Feb. 14, 2014	Jan. 30, 2014	Jan. 15, 2014	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013	Jun. 27, 2014 Series A Preferred Stock	Jun. 15, 2014 Series A Preferred Stock	May 27, 2014 Series A Preferred Stock	May 15, 2014 Series A Preferred Stock	Apr. 28, 2014 Series A Preferred Stock	Apr. 15, 2014 Series A Preferred Stock	Mar. 27, 2014 Series A Preferred Stock	Mar. 15, 2014 Series A Preferred Stock	Feb. 27, 2014 Series A Preferred Stock	Feb. 15, 2014 Series A Preferred Stock	Jan. 27, 2014 Series A Preferred Stock	Jan. 15, 2014 Series A Preferred Stock	Jun. 30, 2014 Series A Preferred Stock	Jun. 30, 2013 Series A Preferred Stock	Jun. 27, 2014 Series B Preferred Stock	Jun. 15, 2014 Series B Preferred Stock	May 27, 2014 Series B Preferred Stock	May 15, 2014 Series B Preferred Stock	Apr. 28, 2014 Series B Preferred Stock	Apr. 15, 2014 Series B Preferred Stock	Mar. 27, 2014 Series B Preferred Stock	Mar. 15, 2014 Series B Preferred Stock	Feb. 27, 2014 Series B Preferred Stock	Feb. 15, 2014 Series B Preferred Stock	Jan. 27, 2014 Series B Preferred Stock	Jan. 15, 2014 Series B Preferred Stock	Jun. 30, 2014 Series B Preferred Stock	Jun. 30, 2013 Series B Preferred Stock
Class of Stock [Line Items]
Dividends declared per common share (in usd per share)		$ 0.05		$ 0.05		$ 0.05		$ 0.05		$ 0.05		$ 0.05	$ 0.15	$ 0.21	$ 0.3	$ 0.45
Rate Per Common Share	$ 0.05		$ 0.05		$ 0.05		$ 0.05		$ 0.05		$ 0.05
Aggregate Amount Paid To Holders Of Record (in Dollars)	$ 17,924		$ 17,924		$ 17,925		$ 17,945		$ 17,954		$ 17,954				$ 107,626	$ 158,543
Preferred stock dividends declared (in usd per share)																		$ 0.171875		$ 0.171875		$ 0.171875		$ 0.171875		$ 0.171875		$ 0.171875				$ 0.16		$ 0.16		$ 0.16		$ 0.16		$ 0.16		$ 0.16
Rate Per Preferred Share																	$ 0.171875		$ 0.171875		$ 0.171875		$ 0.171875		$ 0.171875		$ 0.171875				$ 0.16		$ 0.16		$ 0.16		$ 0.16		$ 0.16		$ 0.16
Aggregate Amount Paid To Holders Of Record (in Dollars)																	$ 375		$ 375		$ 375		$ 375		$ 375		$ 375		$ 2,250	$ 2,232	$ 927		$ 927		$ 927		$ 927		$ 927		$ 927		$ 5,562	$ 4,171