Capital Stock (Details)			1 Months Ended	12 Months Ended
	Oct. 29, 2019 $ / shares shares	Feb. 08, 2018	Feb. 28, 2018	Dec. 31, 2020 $ / shares shares	Dec. 31, 2019 $ / shares shares	Mar. 05, 2020 shares	Oct. 22, 2019 shares	Apr. 19, 2018 shares	Apr. 18, 2018 shares	Jul. 23, 2012 shares	Feb. 27, 2009 USD ($) $ / shares shares
Subsidiary or Equity Method Investee [Line Items]
Preferred stock, shares authorized (in shares)				40,040,000	40,040,000						40,040,000
Preferred stock, par value (in dollars per share) | $ / shares				$ 0.01	$ 0.01						$ 0.01
Preferred stock, shares issued (in shares)				767	767
Preferred stock, Series D, shares outstanding (in shares)				767	767
Stock split, conversion ratio		2	2
Common stock, shares authorized (in shares)				175,000,000	175,000,000			175,000,000	120,000,000
Stock repurchase program, number of shares authorized to be repurchased (in shares)						180,000,000	60,000,000			1,700,000
Stock repurchases (in shares)				5,956,700	390,000
Stock repurchases, average price | $ / shares				$ 19.03	$ 25.97
Maximum
Subsidiary or Equity Method Investee [Line Items]
Preferred stock, liquidation preference, value | $											$ 80,000,000
Series A Preferred Stock | Reliance Bancshares, Inc.
Subsidiary or Equity Method Investee [Line Items]
Preferred stock, shares authorized (in shares)	40,000
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.01
Series B Preferred Stock | Reliance Bancshares, Inc.
Subsidiary or Equity Method Investee [Line Items]
Preferred stock, shares authorized (in shares)	2,000.02
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.01
Convertible Preferred Stock | Reliance Bancshares, Inc.
Subsidiary or Equity Method Investee [Line Items]
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.01
Dividend rate (as percent)	7.00%
Series C Preferred Stock | Reliance Bancshares, Inc.
Subsidiary or Equity Method Investee [Line Items]
Preferred stock, shares authorized (in shares)	140
Preferred stock, shares issued (in shares)	0
Preferred stock, Series D, shares outstanding (in shares)	0
Series D Preferred Stock | Reliance Bancshares, Inc.
Subsidiary or Equity Method Investee [Line Items]
Preferred stock, par value (in dollars per share) | $ / shares	$ 0.01