Loans and Allowance for Credit Losses - Summary of Individually Impaired ACI Loans and Pooled ACI Loans (Details) - USD ($) $ in Thousands		Dec. 31, 2018		Dec. 31, 2017
Financing Receivable Impaired [Line Items]
Recorded Investment in Impaired Loans		$ 249,133		$ 278,587
Commercial and Industrial
Financing Receivable Impaired [Line Items]
Recorded Investment in Impaired Loans		242,048		252,600
Commercial Real Estate
Financing Receivable Impaired [Line Items]
Recorded Investment in Impaired Loans		985		46
Consumer
Financing Receivable Impaired [Line Items]
Recorded Investment in Impaired Loans		3,315	[1]	21,059
ACI Loans and Pooled ACI Loans
Financing Receivable Impaired [Line Items]
Recorded Investment in Impaired Loans	[2]	94,418		115,000
Unpaid Principal Balance		117,832		152,024
Related Specific Allowance		7,924		8,524
Nonaccrual Loans Included in Impaired Loans				225
ACI Loans and Pooled ACI Loans | Commercial and Industrial
Financing Receivable Impaired [Line Items]
Recorded Investment in Impaired Loans	[2]	2,100		13,541
Unpaid Principal Balance		2,331		17,630
Related Specific Allowance		58		5
ACI Loans and Pooled ACI Loans | Commercial Real Estate
Financing Receivable Impaired [Line Items]
Recorded Investment in Impaired Loans	[2]	74,017		82,856
Unpaid Principal Balance		97,613		112,330
Related Specific Allowance		1,641		2,010
Nonaccrual Loans Included in Impaired Loans				225
ACI Loans and Pooled ACI Loans | Consumer
Financing Receivable Impaired [Line Items]
Recorded Investment in Impaired Loans	[2]	18,301		18,603
Unpaid Principal Balance		17,888		22,064
Related Specific Allowance		$ 6,225		$ 6,509

[1] During the third quarter of 2018, the Company began determining the risk rating classification for its consumer portfolio based on delinquency and nonaccrual status in accordance with the Uniform Retail Credit Classification guidance, which contributed to a lower amount of criticized and classified loans from the previous periods.

[2] The recorded investment of a loan also includes any interest receivable, net unearned discount or fees, and unamortized premium or discount.