Benefit Plans - Narrative (Details) - USD ($)	3 Months Ended	12 Months Ended
	Sep. 30, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Employer match of employee contributions (percent)		100.00%
Employer matching contribution maximum percent of employee's eligible compensation (percent)		5.00%
Service period to receive matching contribution		1 year
Vesting period of benefits				3 years
Compensation expense related to 401(k) Plan		$ 7,310,000	$ 6,160,000	$ 5,300,000
Common stock issuable under the deferred compensation plan (shares)		595,705	600,834
Unrecognized losses previously in accumulated other income (loss) recognized upon fund liquidation		$ 0	$ 0	$ 1,558,000
Shares issued through ESPP (in shares)		6,676	34,423	20,928
Executive officers, certain key employees, and board of directors
Defined Benefit Plan Disclosure [Line Items]
Matching contributions to deferred compensation plan		$ 73,000	$ 49,000	$ 162,000
Discretionary contributions to deferred compensation plan		0	0	0
Funded plan | Defined benefit plan
Defined Benefit Plan Disclosure [Line Items]
United contributions to the plan	$ 4,900,000
Unrecognized losses previously in accumulated other income (loss) recognized upon fund liquidation				1,560,000
Pension plan settlement expense				1,380,000
Total settlement loss upon plan termination				$ 2,940,000
Modified Retirement Plan | Unfunded plan
Defined Benefit Plan Disclosure [Line Items]
United contributions to the plan		$ 1,107,000	$ 1,193,000