Employee Benefit Plans - Plan Assets (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Weighted average allocation of plan assets (as a percent)	100.00%	100.00%	100.00%
Defined Benefit Plan Pension Assets Fair Value By Category [Abstract]
Fair value of plan assets	$ 89,972	$ 87,215	$ 75,875
Minimum
Defined Benefit Plan Disclosure [Line Items]
Investment objective period to earn long-term expected rate of return	15 years
Maximum
Defined Benefit Plan Disclosure [Line Items]
Investment objective period to earn long-term expected rate of return	20 years
Level 1
Defined Benefit Plan Pension Assets Fair Value By Category [Abstract]
Fair value of plan assets	$ 149	430
Level 2
Defined Benefit Plan Pension Assets Fair Value By Category [Abstract]
Fair value of plan assets	89,823	86,785
Cash.
Defined Benefit Plan Pension Assets Fair Value By Category [Abstract]
Fair value of plan assets	149	430
Cash. | Level 1
Defined Benefit Plan Pension Assets Fair Value By Category [Abstract]
Fair value of plan assets	$ 149	$ 430
UK and international equities
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Weighted average allocation of plan assets (as a percent)	32.80%	31.40%	29.90%
U.S.
Defined Benefit Plan Pension Assets Fair Value By Category [Abstract]
Fair value of plan assets	$ 17,423	$ 16,201
U.S. | Level 2
Defined Benefit Plan Pension Assets Fair Value By Category [Abstract]
Fair value of plan assets	17,423	16,201
International
Defined Benefit Plan Pension Assets Fair Value By Category [Abstract]
Fair value of plan assets	11,909	10,802
International | Level 2
Defined Benefit Plan Pension Assets Fair Value By Category [Abstract]
Fair value of plan assets	$ 11,909	$ 10,802
UK government and corporate bonds
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Weighted average allocation of plan assets (as a percent)	2.50%	2.70%	12.50%
Corporate bonds / UK Gilts
Defined Benefit Plan Pension Assets Fair Value By Category [Abstract]
Fair value of plan assets	$ 2,292	$ 2,353
Corporate bonds / UK Gilts | Level 2
Defined Benefit Plan Pension Assets Fair Value By Category [Abstract]
Fair value of plan assets	$ 2,292	$ 2,353
Diversified growth fund
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Weighted average allocation of plan assets (as a percent)	25.70%	21.00%	41.30%
Defined Benefit Plan Pension Assets Fair Value By Category [Abstract]
Fair value of plan assets	$ 23,122	$ 18,313
Diversified growth fund | Level 2
Defined Benefit Plan Pension Assets Fair Value By Category [Abstract]
Fair value of plan assets	$ 23,122	$ 18,313
Multi Asset Credit Fund [Member]
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Weighted average allocation of plan assets (as a percent)	4.40%	4.30%
Defined Benefit Plan Pension Assets Fair Value By Category [Abstract]
Fair value of plan assets	$ 3,919	$ 3,713
Multi Asset Credit Fund [Member] | Level 2
Defined Benefit Plan Pension Assets Fair Value By Category [Abstract]
Fair value of plan assets	$ 3,919	$ 3,713
Liability Driven Investments [Member]
Defined Benefit Plan, Plan Assets, Allocations [Abstract]
Weighted average allocation of plan assets (as a percent)	34.60%	40.60%	16.30%
Defined Benefit Plan Pension Assets Fair Value By Category [Abstract]
Fair value of plan assets	$ 31,158	$ 35,403
Liability Driven Investments [Member] | Level 2
Defined Benefit Plan Pension Assets Fair Value By Category [Abstract]
Fair value of plan assets	$ 31,158	$ 35,403