XML 43 R31.htm IDEA: XBRL DOCUMENT
v3.22.0.1

Marketable Investment Securities (Tables) | 12 Months Ended
--- | ---
Dec. 31, 2021
Investments, Debt and Equity Securities [Abstract] |
Schedule of Fair Value for Available-for-Sale Securities by Major Security Type and Class of Security | The amortized cost, gross unrealized holding gains, gross unrealized holding losses, and fair value debt securities classified as available-for-sale securities by major security type and class of security at December 31, 2021 and December 31, 2020 were as follows:
(in millions) | Amortized cost |  | Gross unrealized holding gains |  | Gross unrealized holding losses |  | Estimated fair value
December 31, 2021: |  |  |  |  |  |  |
Cash and cash equivalents: |  |  |  |  |  |  |
Cash | $ | 195.2 |  |  | $ | — |  |  | $ | — |  |  | $ | 195.2 |
Cash equivalents | 63.2 |  |  | — |  |  | — |  |  | 63.2 |
Total cash and cash equivalents | 258.4 |  |  | — |  |  | — |  |  | 258.4 |
Available-for-sale: |  |  |  |  |  |  |
Corporate bonds and notes | 105.7 |  |  | 0.1 |  |  | (0.2) |  |  | 105.6 |
Municipal bonds | 16.1 |  |  | — |  |  | — |  |  | 16.1 |
Federal agency issues | 6.8 |  |  | — |  |  | — |  |  | 6.8 |
US government securities | 11.9 |  |  | — |  |  | — |  |  | 11.9 |
Total | $ | 398.9 |  |  | $ | 0.1 |  |  | $ | (0.2) |  |  | $ | 398.8 |
(in millions) | Amortized cost |  | Gross unrealized holding gains |  | Gross unrealized holding losses |  | Estimated fair value
December 31, 2020: |  |  |  |  |  |  |
Cash and cash equivalents: |  |  |  |  |  |  |
Cash | $ | 47.9 |  |  | $ | — |  |  | $ | — |  |  | $ | 47.9 |
Cash equivalents | 69.1 |  |  | — |  |  | — |  |  | 69.1 |
Total cash and cash equivalents | 117.0 |  |  | — |  |  | — |  |  | 117.0 |
Available-for-sale: |  |  |  |  |  |  |
Corporate bonds and notes | 28.8 |  |  | 0.5 |  |  | — |  |  | 29.3 |
Municipal bonds | 9.4 |  |  | 0.2 |  |  | — |  |  | 9.6 |
Federal agency issues | 4.0 |  |  | — |  |  | — |  |  | 4.0 |
US government securities | 11.7 |  |  | 0.1 |  |  | — |  |  | 11.8 |
Total | $ | 170.9 |  |  | $ | 0.8 |  |  | $ | — |  |  | $ | 171.7 |
Schedule of Cash, Cash Equivalents, and Maturities of Debt Securities Classified as Available-For-Sale Securities | Cash, cash equivalents, and maturities of debt securities classified as available-for-sale are as follows at December 31, 2021:
(in millions) | Amortized cost |  | Estimated fair value
Cash | 195.2 |  |  | 195.2 |
Cash equivalents | 63.2 |  |  | 63.2 |
Available-for-sale: |  |  |
Due within one year | 80.3 |  |  | 80.4 |
Due after one year through five years | 60.2 |  |  | 60.0 |
Due after five years | — |  |  | — |
Total | $ | 398.9 |  |  | $ | 398.8 |

X
- Definition Tabular disclosure of maturities of an entity's investments as well as any other information pertinent to the investments. + References No definition available. + Details
Name: | us-gaap_InvestmentsClassifiedByContractualMaturityDateTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration

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

X
- Definition Tabular disclosure of the reconciliation of available-for-sale securities from cost basis to fair value. + References No definition available. + Details
Name: | us-gaap_ScheduleOfAvailableForSaleSecuritiesReconciliationTableTextBlock
Namespace Prefix: | us-gaap_
Data Type: | dtr-types:textBlockItemType
Balance Type: | na
Period Type: | duration