Consolidated Balance Sheet (Unaudited) (Parenthetical) - USD ($) $ in Thousands	Jun. 30, 2019	Dec. 31, 2018
Pledged securities that can be sold or repledged	$ 167,935	$ 487,365
Investment securities, available for sale, amortized cost	7,359,445	8,869,423
Investment securities, held to maturity, fair value	3,630,158	3,255,483
Equity and other securities, cost	$ 558,440	$ 677,187
Preferred stock, par value	$ 1.00	$ 1.00
Preferred stock, shares authorized	1,000,000	1,000,000
Common stock, par value	$ 0.50	$ 0.50
Common stock, shares authorized	250,000,000	250,000,000
Common stock, shares issued	159,741,898	159,765,044
Common stock issuable, shares	21,327	24,563
Treasury stock, common shares	25,563,347	21,255,275
Series A Series C Series And E Preferred Stock [Member]
Preferred stock, shares issued	731,500	731,500
Preferred stock, shares outstanding	731,500	731,500
Preferred stock, liquidation preference per share	$ 1,000	$ 1,000
Series F Preferred Stock [Member]
Preferred stock, shares issued	50,000	50,000
Preferred stock, shares outstanding	50,000	50,000
Preferred stock, liquidation preference per share	$ 10,000	$ 10,000