Capital Stock - Textual (Details) - USD ($)	3 Months Ended		9 Months Ended		20 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Jun. 30, 2021	Jul. 23, 2021	Jul. 22, 2021	Dec. 31, 2020	Oct. 29, 2019	Feb. 27, 2009
Class of Stock [Line Items]
Preferred stock, shares authorized (in shares)	40,040,000		40,040,000					40,040,000		40,040,000
Preferred stock, par value (in dollars per share)	$ 0.01		$ 0.01					$ 0.01		$ 0.01
Number of shares authorized to be repurchased (in shares)						276,500,000	180,000,000
Stock repurchases (in shares)	1,806,205	0	1,937,121	4,922,336	178,000,000
Stock repurchases, average price (in dollars per share)	$ 28.48		$ 28.14	$ 18.96
Maximum
Class of Stock [Line Items]
Preferred stock, liquidation preference, value										$ 80,000,000
Reliance Bancshares, Inc. | Series D Preferred Stock
Class of Stock [Line Items]
Preferred stock, par value (in dollars per share)									$ 0.01