Assets Held for Sale - Assets and Liabilities Held for Sale (Details) - USD ($) $ in Thousands	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Current assets
Cash and cash equivalents included in assets held for sale	$ 941	$ 0	$ 0
Assets held for sale	5,242	0
Current liabilities
Liabilities held for sale	1,793	$ 0
Discontinued Operations, Held-for-sale | Puerto Rican Radiopharmacy Servicing Subsidiary
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Purchase price for stock	18,000
Current assets
Cash and cash equivalents included in assets held for sale	941
Accounts receivable, net	2,191
Inventory	420
Other current assets	43
Assets held for sale	3,595
Assets, Noncurrent [Abstract]
Property, plant and equipment, net	761
Intangibles, net	96
Other long-term assets	790
Total assets held for sale	5,242
Current liabilities
Accounts payable	224
Accrued expenses and other liabilities	661
Liabilities held for sale	885
Liabilities, Noncurrent [Abstract]
Asset retirement obligations	302
Other long-term liabilities	606
Liabilities	$ 1,793