Revenue Recognition - Summary of Noninterest Income Segregated by Revenue Streams In-Scope and Out-of-Scope of Topic 606 (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Disaggregation of Revenue [Line Items]
Service Charges on Deposit Accounts	$ 6,027	$ 7,592	$ 18,575	$ 22,239
Fees, Exchange, and Other Service Charges	12,296	14,900	34,913	43,360
Annuity and Insurance	881	1,278	2,692	5,662
Other	7,046	6,765	23,574	18,756
Noninterest Income	41,734	46,507	139,151	135,636
Accounting Standards Update 2014-09
Disaggregation of Revenue [Line Items]
Noninterest Income	41,734	46,507	139,151	135,636
Accounting Standards Update 2014-09 | Noninterest Income In Scope of Topic 606
Disaggregation of Revenue [Line Items]
Trust and Asset Management	10,752	10,930	32,217	33,076
Service Charges on Deposit Accounts	3,000	3,268	8,770	9,912
Fees, Exchange, and Other Service Charges	9,130	11,705	26,489	34,859
Annuity and Insurance	855	1,251	2,605	5,567
Other	2,131	2,224	6,697	7,200
Noninterest Income	25,868	29,378	76,778	90,614
Accounting Standards Update 2014-09 | Noninterest Income Out of Scope of Topic 606
Disaggregation of Revenue [Line Items]
Noninterest Income	$ 15,866	$ 17,129	$ 62,373	$ 45,022