Stockholders' Equity (Narrative) (Details) $ / shares in Units, $ in Millions			12 Months Ended
	Jan. 26, 2023 shares	Apr. 22, 2021 shares	Dec. 31, 2023 USD ($) $ / shares shares	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2018
Equity, Class of Treasury Stock [Line Items]
Treasury stock, shares			6,300,000	6,300,000
Treasury stock, Cost basis | $			$ 236.7	$ 238.6
Shares repurchased				1,204,368	449,876
Minimum risk-based capital ratio			0.08	0.08		0.08
Minimum Tier 1 common equity			4.50%	4.50%		4.50%
Minimum Tier 1 capital ratio			0.06	0.06		0.06
Minimum Tier 1 leverage capital ratio			0.04	0.04		0.04
Well capitalized total risk based capital ratio			0.10	0.10		0.10
Well capitalized Tier 1 common equity			6.50%	6.50%		6.50%
Well capitalized Tier 1 risk-based capital ratio			0.08	0.08		0.08
Well capitalized Tier 1 leverage capital ratio			0.05	0.05		0.05
Minimum requirement of capital conservation buffer ratio			2.50%
Topic 326 [Member]
Equity, Class of Treasury Stock [Line Items]
Regulatory capital modified transition amount percentage			25.00%
Impact of modified transition amount | $					$ 24.9
Impact of modified transition amount net of tax | $					$ 44.1
Topic 326 [Member] | Regulatory Capital Transition For 2020 and 2021 [Member]
Equity, Class of Treasury Stock [Line Items]
Regulatory capital transition percentage			0.00%
Topic 326 [Member] | Regulatory Capital Three Year Transition, Year 2022 [Member]
Equity, Class of Treasury Stock [Line Items]
Regulatory capital transition percentage			25.00%
Topic 326 [Member] | Regulatory Capital Three Year Transition, Year 2023 [Member]
Equity, Class of Treasury Stock [Line Items]
Regulatory capital transition percentage			50.00%
Topic 326 [Member] | Regulatory Capital Three Year Transition, Year 2024 [Member]
Equity, Class of Treasury Stock [Line Items]
Regulatory capital transition percentage			75.00%
Topic 326 [Member] | Regulatory Capital Three Year Transition, Year 2024 and Thereafter [Member]
Equity, Class of Treasury Stock [Line Items]
Regulatory capital transition percentage			100.00%
Bank Holding Companies and Banks that Meet Certain Criteria [Member]
Equity, Class of Treasury Stock [Line Items]
Minimum Tier 1 leverage capital ratio						0.03
2018 Stock Buyback Program [Member]
Equity, Class of Treasury Stock [Line Items]
Number of shares authorized for repurchase	4,300,000	4,300,000
Stock repurchase expiration date	Dec. 31, 2024	Dec. 31, 2022
2018 Stock Buyback Program [Member] | Common Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Shares repurchased			1,654,244	1,204,368
Shares purchased average cost per share | $ / shares			$ 48.77	$ 48.9
Restricted Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Number of shares nonvested			300,000	700,000