Summary of Significant Accounting Policies - The Balances in the Company's Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 209,325,000	$ 189,100,000
Total other comprehensive income (loss)	570,000	411,000
Ending balance	224,138,000	194,253,000
Foreign Currency [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(13,935,000)	(13,974,000)
Other comprehensive income (loss) before reclassifications	570,000	(411,000)
Total other comprehensive income (loss)	570,000	(411,000)
Ending balance	(13,365,000)	(13,563,000)
Defined Benefit Pension Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(1,466,000)	(1,799,000)
Other comprehensive income (loss) before reclassifications	0	0
Total other comprehensive income (loss)	0	0
Ending balance	(1,466,000)	(1,799,000)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(15,401,000)	(15,773,000)
Other comprehensive income (loss) before reclassifications	570,000	(411,000)
Total other comprehensive income (loss)	570,000	(411,000)
Ending balance	$ (14,831,000)	$ (15,362,000)