Income Taxes - Components of Net Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Thousands	Dec. 31, 2016	Dec. 31, 2015
Assets:
Deferred compensation expense	$ 86,327	$ 88,749
Allowance for loan and lease losses and nonperforming assets	54,310	53,964
Investment securities	47,453	23,627
Deferred income and expense	435	7,725
State income taxes	14,293	9,496
Total deferred income tax assets	202,818	183,561
Liabilities:
Leases	(39,397)	(45,908)
Intangible assets	(1,792)	(2,186)
Other	(9,793)	(9,327)
Total deferred income tax liabilities	(50,982)	(57,421)
Net deferred income tax assets	$ 151,836	$ 126,140