Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Dec. 31, 2018	Dec. 31, 2017
Statement of Financial Position [Abstract]
Mortgage loans held for sale, fair value	$ 219,848	$ 108,316
Preferred stock, par value (usd per share)	$ 0.01	$ 0.01
Preferred stock, shares authorized (shares)	5,000,000	5,000,000
Preferred stock, shares issued (shares)	0	0
Preferred stock, shares outstanding (shares)	0	0
Common stock, par value (usd per share)	$ 5	$ 5
Common stock, shares authorized (shares)	150,000,000	150,000,000
Common stock, shares issued (shares)	59,296,725	49,990,248
Common stock, shares outstanding (shares)	58,546,480	49,321,231
Treasury stock (in shares)	750,245	669,017