Benefit Plans - Narrative (Details)	1 Months Ended		12 Months Ended
	May 31, 2012 shares	May 31, 2004 shares	Dec. 31, 2020 USD ($) shares	Dec. 31, 2019 USD ($) shares	Dec. 31, 2018 USD ($)	May 31, 2017 shares	May 31, 2015 shares	May 31, 2014 shares
Defined Benefit Plan Disclosure [Line Items]
Employer's match of employees' contributions of the first 3% of eligible compensation (as a percent)			100.00%	100.00%	100.00%
Percentage of eligible compensation, matched 100% by employer			3.00%	3.00%	3.00%
Employer's match of employees' contributions of the next 2% of eligible compensation (as a percent)			50.00%	50.00%	50.00%
Percentage of eligible compensation, matched 50% by employer			2.00%	2.00%	2.00%
Contributions made | $			$ 4,100,000	$ 2,900,000	$ 2,500,000
Intrinsic value | $			1,700,000	4,200,000	8,400,000
Deferred Compensation Arrangement with Individual, by Type of Compensation, Pension and Other Postretirement Benefits | Opus
Defined Benefit Plan Disclosure [Line Items]
Deferred compensation liability | $			98,000
Supplemental Employee Retirement Plan | Deferred Compensation Arrangement with Individual, by Type of Compensation, Pension and Other Postretirement Benefits | Plaza Bancorp
Defined Benefit Plan Disclosure [Line Items]
Deferred compensation liability | $			1,700,000	1,800,000
Supplemental Employee Retirement Plan | Deferred Compensation Arrangement with Individual, by Type of Compensation, Pension and Other Postretirement Benefits | Executive Officer
Defined Benefit Plan Disclosure [Line Items]
Amounts expensed | $			511,000	674,000	827,000
Amounts recorded as liability | $			$ 10,400,000	$ 10,800,000	10,900,000
Stock option
Defined Benefit Plan Disclosure [Line Items]
Number of options outstanding (in shares)			309,315	453,104
Granted (in shares)			9,538
Compensation expense | $			$ 8,000	$ 132,000	571,000
Unrecognized compensation expense | $			0
Restricted Stock
Defined Benefit Plan Disclosure [Line Items]
Compensation expense | $			10,800,000	$ 10,400,000	$ 8,500,000
Unrecognized compensation expense | $			16,900,000
Grant date fair value | $			$ 15,700,000
Weighted-average period of recognition			2 years 3 months 25 days
2004 Long-Term Incentive Plan
Defined Benefit Plan Disclosure [Line Items]
Number of shares authorized (in shares)		525,500
Term of plan (in years)		10 years
Vesting percentage per year		33.30%
Number of options outstanding (in shares)			0
Granted (in shares)			0
2012 Plan
Defined Benefit Plan Disclosure [Line Items]
Number of shares authorized (in shares)	620,000					3,580,000		800,000
Term of plan (in years)	10 years
Number of options outstanding (in shares)			279,466
Granted (in shares)			2,168,227
2014 Plan
Defined Benefit Plan Disclosure [Line Items]
Number of shares authorized (in shares)								1,420,000
2017 Plan
Defined Benefit Plan Disclosure [Line Items]
Number of shares authorized (in shares)						5,000,000
2015 Equity Based Compensation Plan
Defined Benefit Plan Disclosure [Line Items]
Number of shares authorized (in shares)			250,000				630,473
Shares issued ratio, actual number of shares							2
Number of options outstanding (in shares)			16,358
Granted (in shares)			656,450
2005 Long-Term Incentive Plan
Defined Benefit Plan Disclosure [Line Items]
Number of options outstanding (in shares)			13,491
Granted (in shares)			0
Minimum
Defined Benefit Plan Disclosure [Line Items]
Employee contribution, as a percentage of compensation			1.00%
Minimum | 2012 Plan
Defined Benefit Plan Disclosure [Line Items]
Award vesting period (in years)	1 year
Maximum
Defined Benefit Plan Disclosure [Line Items]
Employee contribution, as a percentage of compensation			99.00%
Maximum | 2012 Plan
Defined Benefit Plan Disclosure [Line Items]
Award vesting period (in years)	5 years