Loans - Loans Sales (Details) - USD ($) $ in Thousands		3 Months Ended		6 Months Ended
		Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2020	Jun. 30, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total net gains on loan sales		$ 4,601	$ 1,981	$ 7,230	$ 3,391
Corporate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments for loan purchases	[1]	36,152	132,034	182,613	189,573
Consumer Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments for loan purchases	[1]	179,410	270,692	394,552	381,874
Corporate loan sales
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales		295	2,178	4,598	5,376
Less book value of loans sold		289	2,132	4,477	5,248
Total net gains on loan sales	[2]	6	46	121	128
1-4 family mortgage loan sales
Accounts, Notes, Loans and Financing Receivable [Line Items]
Proceeds from sales		173,251	95,408	292,410	154,191
Less book value of loans sold		168,656	93,473	285,301	150,928
Total net gains on loan sales	[3]	4,595	1,935	7,109	3,263
1-4 family mortgage loan sales | Consumer Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments for loan purchases	[1]	179,410	231,533	249,585	304,463
Commercial and industrial | Corporate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments for loan purchases	[1]	22,894	128,891	168,716	181,610
Office, retail, and industrial | Corporate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments for loan purchases	[1]	0	1,711	0	1,711
Construction | Corporate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments for loan purchases	[1]	3,258	1,432	3,897	2,266
Other commercial real estate | Corporate Loans
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments for loan purchases	[1]	10,000	0	10,000	3,986
Home equity | Consumer Loan
Accounts, Notes, Loans and Financing Receivable [Line Items]
Payments for loan purchases	[1]	$ 0	$ 39,159	$ 144,967	$ 77,411

[1] Consists of the Company's portion of loan participations purchased.

[2] Net gains on corporate loan sales are included in other service charges, commissions, and fees in the Condensed Consolidated Statements of Income.

[3] Net gains on 1-4 family mortgage loan sales are included in mortgage banking income in the Condensed Consolidated Statements of Income.⁽³⁾Consists of the Company's portion of loan participations purchased.