Sales of Certain International Segment Assets (Detail) $ in Thousands, $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2016 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 AUD ($)	Dec. 31, 2016 USD ($)
Assets Of Disposal Group Including Discontinued Operation [Line Items]
Gain on sale of assets		$ 0	$ 0		$ 6,385
Canadian Radiopharmacies and Gludef Manufacturing and Distribution Business
Assets Of Disposal Group Including Discontinued Operation [Line Items]
Purchase price for asset sale	$ 9,000
Working capital adjustment	$ 500
Gain on sale of assets					5,900
Australian Radiopharmacy Servicing Subsidiary
Assets Of Disposal Group Including Discontinued Operation [Line Items]
Gain on sale of assets					500
Share sale price				$ 2.0	1,500
Working capital adjustment in sale of stock units				2.0	1,500
Gross proceeds from sale of stock units				$ 4.0	3,000
Net proceeds from sale of stock units					2,200
Working Capital Assets Liabilities Sold					2,000
Reclassification from other comprehensive income to gain on sales of assets					$ 400