XML 59 R37.htm IDEA: XBRL DOCUMENT
v3.10.0.1

Investments in Marketable Securities (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2018
Marketable Securities [Abstract] |
Schedule of Cost, Gross Unrealized Gains and Losses, and Fair Value of Investments | The following is a summary of the cost, gross unrealized gains and losses and fair value of Investments in marketable securities:
|  | December 31,
|  | 2017 |  | 2018
Cost |  | $ | 67.1 |  |  | $ | 126.8 |
Unrealized gains |  | 13.0 |  |  | 1.1 |
Unrealized losses |  | (2.3 | ) |  | (8.6 | )
Fair value |  | $ | 77.8 |  |  | $ | 119.3 |

X
- References No definition available. + Details
Name: | us-gaap_MarketableSecuritiesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Tabular disclosure of marketable securities. This may consist of investments in certain debt and equity securities, short-term investments and other assets. + References No definition available. + Details
Name: | us-gaap_MarketableSecuritiesTextBlock
Namespace Prefix: | us-gaap_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration