Consolidated Balance Sheets (Parentheticals) - USD ($) $ in Thousands	Dec. 31, 2019	Dec. 31, 2018
Assets of consolidated variable interest entities	$ 245,489	$ 239,012
Liabilities of consolidated variable interest entities	$ 153,436	$ 143,186
Preferred stock, par value (in dollars per share)	$ 1.00	$ 1.00
Preferred stock, shares authorized (in shares)	7,054,000	7,054,000
Preferred stock, shares issued (in shares)	19,580	42,580
Preferred stock, shares outstanding (in shares)	19,580	42,580
Preferred stock, liquidation preference	$ 489,500	$ 1,064,500
Preferred stock, undesignated (in shares)	6,019,240	5,996,240
Common stock, par value (in dollars per share)	$ 0.01	$ 0.01
Common stock, shares authorized (in shares)	750,000,000	750,000,000
Common stock, shares issued (in shares)	431,814,951	421,388,879
Common stock, shares outstanding (in shares)	431,814,951	421,388,879