Capital Stock (Details)			1 Months Ended	12 Months Ended
	Oct. 29, 2019 $ / shares shares	Feb. 08, 2018	Feb. 28, 2018	Dec. 31, 2019 USD ($) $ / shares shares	Dec. 31, 2018 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
Preferred stock, par value (in dollars per share) | $ / shares				$ 0.01						$ 0.01
Preferred stock, shares issued (in shares)				767
Preferred stock, Series D, shares outstanding (in shares)				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)						60,000,000			1,700,000
Stock repurchases (in shares)				390,000	0
Stock repurchases, average price | $				$ 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