CONSOLIDATED BALANCE SHEETS PARENTHETICAL - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Statement of Financial Position [Abstract]
Available for Sale at Fair value - Amortized cost	$ 30,211,787	$ 28,322,977
Preferred stock par value	$ 0.01	$ 0.01
Preferred stock shares authorized	10,000,000	10,000,000
Preferred stock shares issued	0	0
Preferred stock shares outstanding	0	0
Common stock par value	$ 0.01	$ 0.01
Common stock shares authorized	140,000,000	140,000,000
Common Stock, Shares, Issued	79,137,758	79,137,758
Common stock shares outstanding	64,302,502	65,204,526
Treasury Shares Held	14,835,256	13,933,232
Allowances for Loan and Lease Losses, Real Estate	$ 7,685	$ 6,813