Premises and Equipment - Summary of Premises and Equipment (Detail) - USD ($) $ in Thousands	Dec. 31, 2017	Dec. 31, 2016
Property, Plant and Equipment [Line Items]
Land	$ 98,077	$ 104,671
Buildings	454,610	448,442
Leasehold improvements	239,956	232,936
Premises and equipment, gross	1,487,347	1,437,117
Less: accumulated depreciation and amortization	840,896	761,854
Premises and equipment, net	646,451	675,263
Owned Assets [Member]
Property, Plant and Equipment [Line Items]
Furniture and equipment	676,665	636,219
Less: accumulated depreciation and amortization	830,832	756,245
Capital Leases [Member]
Property, Plant and Equipment [Line Items]
Furniture and equipment	18,039	14,849
Less: accumulated depreciation and amortization	$ 10,064	$ 5,609