Consolidated Balance Sheets (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2019	Dec. 31, 2018
Statement of Financial Position [Abstract]
Mortgage loans held for sale measured at fair value	$ 392,448	$ 219,848
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)	$ 5.00	$ 5.00
Common stock, shares authorized (shares)	150,000,000	150,000,000
Common stock, shares issued (shares)	59,296,725	59,296,725
Common stock, shares outstanding (shares)	57,455,306	58,546,480
Treasury stock (in shares)	1,841,419	750,245