Consolidated Statements of Financial Position (Parenthetical) - USD ($) $ in Thousands	Sep. 30, 2016	Dec. 31, 2015
Held-to-maturity, fair value	$ 575,144	$ 512,705
Accumulated depreciation of premises and equipment	$ 124,986	$ 120,382
Preferred stock, no par value (in dollars per share)
Preferred stock, shares authorized (in shares)	2,000,000	2,000,000
Preferred stock, shares issued (in shares)	0	0
Common stock, par value (in dollars per share)	$ 1	$ 1
Common stock, shares authorized (in shares)	100,000,000	60,000,000
Common stock, shares issued (in shares)	70,497,027	38,167,861
Common stock, shares outstanding (in shares)	70,497,027	38,167,861