Stockholders' Equity (Narrative) (Details) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2024 USD ($) $ / shares shares	Dec. 31, 2023 USD ($) shares	Dec. 31, 2022 shares	Dec. 31, 2021 USD ($)	Dec. 09, 2024 shares	Jan. 26, 2023 shares	Dec. 31, 2018
Equity, Class of Treasury Stock [Line Items]
Treasury stock, shares	6,700,000	6,300,000
Treasury stock, Cost basis | $	$ 264.1	$ 236.7
Shares repurchased	762,993		1,204,368
Excise tax | $	$ 0.1
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
2018 Stock Buyback Program [Member] | Common Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Shares repurchased	762,993	0
Shares purchased average cost per share | $ / shares	$ 49.4
Restricted Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Number of shares nonvested	100,000	300,000