Divestitures - Additional Information (Detail) - USD ($) |
12 Months Ended | ||
---|---|---|---|
Dec. 31, 2019 |
Dec. 31, 2018 |
Dec. 31, 2017 |
|
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items] | |||
Gain (loss) on divestiture and sale of investments | $ 18,421,000 | $ 561,000 | |
Other Sales [Member] | |||
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items] | |||
Gain (loss) on divestiture and sale of investments | $ 18,400,000 | $ 0 | $ 0 |