Stockholders' Equity (Narrative) (Details) $ / shares in Units, $ in Millions		12 Months Ended
	Apr. 22, 2021 shares	Dec. 31, 2022 USD ($) $ / shares shares	Dec. 31, 2021 USD ($) shares	Dec. 31, 2020 shares	Dec. 31, 2018
Equity, Class of Treasury Stock [Line Items]
Treasury stock shares		6,300,000	5,100,000
Treasury stock, Cost basis | $		$ 238.6	$ 175.8
Shares repurchased		1,204,368	449,876	315,851
Minimum risk-based capital ratio		0.0800	0.0800		0.080
Minimum Tier 1 common equity		4.50%	4.50%		4.50%
Minimum Tier 1 capital ratio		0.0600	0.0600		0.060
Minimum Tier 1 leverage capital ratio		0.0400	0.0400		0.040
Well capitalized total risk based capital ratio		0.1000	0.1000		0.100
Well capitalized Tier 1 common equity		6.50%	6.50%		6.50%
Well capitalized Tier 1 risk-based capital ratio		0.0800	0.0800		0.080
Well capitalized Tier 1 leverage capital ratio		0.0500	0.0500		0.050
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					0.030
Accelerated Share Repurchase Agreement | Common Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Shares repurchased		1,654,244
Shares purchased average cost per share | $ / shares		$ 48.77
2018 Stock Buyback Program [Member]
Equity, Class of Treasury Stock [Line Items]
Number of shares authorized for repurchase	4,300,000
Stock repurchase expiration date	Dec. 31, 2022
2018 Stock Buyback Program [Member] | Common Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Shares repurchased		1,204,368
Shares purchased average cost per share | $ / shares		$ 48.90
Restricted Stock [Member]
Equity, Class of Treasury Stock [Line Items]
Number of shares nonvested		700,000	1,100,000