Income Taxes (Deferred Tax Assets and Liabilities) (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Income Taxes [Abstract]
Allowance for loan losses	$ 89,120	$ 72,940
Employee compensation and benefits	28,401	26,853
Loan purchase accounting adjustments	12,047	18,977
Tax credit carryforward	29,085	42,850
Securities	23,169	5,038
State net operating loss	1,690	1,910
Other	14,583	10,928
Gross deferred tax assets	198,095	179,496
State valuation allowance	(1,690)	(1,910)
Subtotal valuation allowance	(1,690)	(1,910)
Net deferred tax assets	196,405	177,586
Fixed assets & intangibles	(74,518)	(80,389)
FDIC indemnification asset	(6,293)	(10,688)
Other	(11,159)	(10,679)
Gross deferred tax liabilities	(91,970)	(101,756)
Net deferred tax asset	$ 104,435	$ 75,830