| In millions, except per share items | Dec-31-20 | Sep-30-20 | Jun-05-20 | Mar-31-20 | Dec-31-19 | Sep-30-19 | Jun-30-19 | Jun-05-19 |
| | 10-K | 10-Q | 8-K | 10-Q | 10-K | 10-Q | 10-Q | 8-K |
| Cash flows from operating activities: | | | | | | | | |
| Net income | | 206.7 | | 239.5 | 243.1 | 198.4 | 158.3 | |
| Adjustments to reconcile net income to net cash from operating activities: | | | | | | | | |
| Depreciation and amortization expense | | 95.0 | | 119.6 | 114.9 | 85.0 | 112.6 | |
| Amortization of debt issuance costs and discount | | 1.3 | | 1.8 | 1.8 | 1.4 | 1.9 | |
| Amortization of terminated interest rate swaps | | 7.7 | | 6.5 | 6.5 | 5.0 | 6.8 | |
| Stock-based compensation expense | | 50.2 | | 52.0 | 45.8 | 29.2 | 35.6 | |
| Unrealized foreign currency losses (gains) | | 13.9 | | -3.3 | -6.5 | -19.3 | -0.5 | |
| Change in fair value of acquisition-related contingent consideration | | -43.9 | | 0.6 | | | | |
| Deferred income taxes | | -17.6 | | -31.9 | -23.9 | -19.3 | -26.4 | |
| Other reconciling items | | 8.2 | | 0.8 | 0.6 | 0.2 | -0.1 | |
| Changes in operating assets and liabilities, net of acquired assets and assumed liabilities: | | | | | | | | |
| Prepaid expenses and other assets | | | | | -13.7 | | | |
| Income taxes | | | | | -31.0 | | | |
| Payment of acquisition-related contingent consideration | | | | | | -118.3 | | |
| Net cash provided by operating activities | | 428.8 | | 273.1 | 253.6 | 243.0 | 237.8 | |
| |
| Cash flows from investing activities: | | | | | | | | |
| Purchase of fixed assets | | -88.6 | | -75.9 | -74.3 | -56.0 | -70.2 | |
| Proceeds from the sale of fixed assets | | 0.1 | | 0.1 | | | 0.1 | |
| Cash (paid) received for interest on interest rate swap | | -7.6 | | -0.5 | 0.7 | 0.7 | 1.3 | |
| Acquisition of Care Innovations, Inc., net of cash acquired | | | | -159.1 | | | | |
| Net cash used in investing activities | | -213.2 | | -235.4 | -73.2 | -54.9 | -68.2 | |
| |
| Cash flows from financing activities: | | | | | | | | |
| Proceeds from issuance of long-term debt | | | | | 1,300.0 | 300.0 | | |
| Repayment of long-term debt | | | | | -1,216.5 | | | |
| Borrowings on line of credit | | 393.8 | | 333.8 | 233.8 | | 40.0 | |
| Repayments of line of credit | | -215.0 | | -200.0 | -145.0 | | -40.0 | |
| Payment for debt issuance costs | | -5.5 | | -5.0 | -4.5 | | | |
| Acquisition of noncontrolling interest | | | | | | -4.1 | | |
| Proceeds from stock issued under employee stock purchase plan and stock option exercises | | 48.3 | | 38.3 | 45.8 | 37.9 | 43.9 | |
| Taxes paid related to net shares settlement of equity awards | | | | | -0.1 | | | |
| Repurchase and retirement of common stock | | | | | | -300.0 | | |
| Net cash provided by (used in) financing activities | | -75.7 | | -59.9 | -90.7 | -97.1 | -150.7 | |
| Effects of foreign exchange changes on cash, cash equivalents, and restricted cash | | -7.2 | | -4.5 | 1.9 | -1.7 | -0.1 | |
| Change in cash, cash equivalents, and restricted cash | | 69.0 | | -26.8 | 91.6 | 89.3 | 18.7 | |