Summary of Significant Accounting Policies - The Balances in the Company's Accumulated Other Comprehensive Income (Loss) (Details) - USD ($)	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	$ 224,138,000	$ 194,253,000	$ 209,325,000	$ 189,100,000
Total other comprehensive income	(1,179,000)	470,000	(609,000)	881,000
Ending balance	237,258,000	201,981,000	237,258,000	201,981,000
Foreign Currency [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(13,365,000)	(13,563,000)	(13,935,000)	(13,974,000)
Other comprehensive income (loss) before reclassifications	(1,179,000)	470,000	(609,000)	881,000
Total other comprehensive income	(1,179,000)	470,000	(609,000)	881,000
Ending balance	(14,544,000)	(13,093,000)	(14,544,000)	(13,093,000)
Defined Benefit Pension Plans [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(1,466,000)	(1,799,000)	(1,466,000)	(1,799,000)
Other comprehensive income (loss) before reclassifications			0	0
Total other comprehensive income			0	0
Ending balance	(1,466,000)	(1,799,000)	(1,466,000)	(1,799,000)
Accumulated Other Comprehensive Income (Loss) [Member]
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning balance	(14,831,000)	(15,362,000)	(15,401,000)	(15,773,000)
Other comprehensive income (loss) before reclassifications	(1,179,000)	470,000	(609,000)	881,000
Total other comprehensive income	(1,179,000)	470,000	(609,000)	881,000
Ending balance	$ (16,010,000)	$ (14,892,000)	$ (16,010,000)	$ (14,892,000)