Earnings Per Share - Preferred stock dividends (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Accrued dividends on preferred stock, including accretion of discounts
Total preferred stock dividends	$ 3,052	$ 3,030
Series A - 6% fixed
Accrued dividends on preferred stock, including accretion of discounts
Total preferred stock dividends	3	3
Series B - 5% fixed until December 6, 2013, 9% thereafter
Accrued dividends on preferred stock, including accretion of discounts
Total preferred stock dividends	2,630	2,608
Series D - LIBOR plus 9.6875%, resets quarterly
Accrued dividends on preferred stock, including accretion of discounts
Total preferred stock dividends	$ 419	$ 419