Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Loans held for sale at fair value	$ 2,117,510	$ 1,757,807
Preferred stock, par value (usd per share)	$ 1.00	$ 1.00
Preferred stock, liquidation preference (usd per share)	$ 25.00	$ 25.00
Preferred stock, shares authorized	100,000,000	100,000,000
Preferred stock, shares issued	9,000,000	2,300,000
Preferred stock, shares outstanding	9,000,000	2,300,000
Common stock, par value (usd per share)	$ 1.00	$ 1.00
Common stock, shares authorized	200,000,000	200,000,000
Common stock, shares issued	30,820,177	27,432,061
Common stock, shares outstanding	30,289,917	26,901,801
Treasury stock, shares	530,260	532,260