| In millions, except per share items | Dec-31-14 | Dec-31-13 | Dec-31-12 | Dec-31-11 | Dec-31-10 | Dec-31-09 | Dec-31-08 | Dec-31-07 |
| | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K | 10-K |
| Cash flows from operating activities: | | | | | | | | |
| Net income | 373.7 | 298.7 | 121.0 | 91.8 | 64.7 | | | |
| Items not involving cash: | | | | | | | | |
| Stock-based compensation | 33.6 | 25.6 | 17.7 | 9.4 | 5.9 | 3.7 | | |
| Depreciation of property and equipment | 63.5 | 42.2 | 20.2 | 9.5 | 8.4 | 8.0 | | |
| Amortization of intangible assets | 213.2 | 203.2 | 130.1 | 16.4 | 7.9 | 9.7 | | |
| Deferred lease inducements and rent | 5.5 | 28.1 | 3.1 | 0.8 | -0.5 | -0.6 | | |
| Deferred income taxes | -58.0 | -44.3 | -37.9 | -5.9 | 3.3 | -0.3 | | |
| Tax benefit on option exercises | -3.5 | -9.7 | -19.4 | -10.8 | -13.1 | -4.5 | | |
| Deferred financing cost amortization | 9.6 | 9.1 | 5.0 | | | | | |
| Changes in operating assets and liabilities, net of effects from acquisitions: | | | | | | | | |
| Accounts receivable | -294.7 | -217.5 | -134.3 | -110.5 | -9.5 | -16.7 | | |
| Rebates receivable | -558.1 | 3.0 | -41.0 | 5.3 | -16.6 | 12.0 | | |
| Other current assets | -44.6 | -25.3 | 82.8 | 10.2 | 10.2 | 0.0 | | |
| Accounts payable | 150.0 | 149.4 | 70.6 | 94.8 | 25.1 | 1.6 | | |
| Accrued expenses and other current liabilities | 72.6 | -43.7 | 1.7 | | | | | |
| Rebates payable | 611.5 | 39.6 | 60.9 | | | | | |
| Other long-term assets and liabilities | 16.1 | 17.0 | -30.9 | -1.1 | 1.0 | 1.6 | | |
| Net cash provided by operating activities | 590.2 | 475.4 | 249.7 | 94.7 | 96.3 | 86.4 | | |
| |
| Cash flows from investing activities: | | | | | | | | |
| Acquisition, net of cash acquired | -2.0 | -388.9 | -1,565.7 | -79.8 | -99.2 | -2.2 | | |
| Purchases of property and equipment | -78.1 | -128.8 | -40.2 | -9.7 | -9.1 | -9.0 | | |
| Net cash used by investing activities | -60.1 | -497.7 | -1,605.9 | -89.5 | -103.7 | -15.8 | | |
| |
| Cash flows from financing activities: | | | | | | | | |
| Proceeds from issuance of debt | 492.5 | 450.0 | 1,475.4 | | | | | |
| Repayment of long-term debt | -337.5 | -362.5 | -617.0 | | | -47.6 | | |
| Payment of financing costs | -2.0 | -2.3 | -18.8 | -1.6 | | | | |
| Proceeds from exercise of options | 5.6 | 3.0 | 7.8 | 5.7 | 11.0 | 6.3 | | |
| Tax benefit on option exercises | 3.5 | 9.7 | 19.4 | 10.8 | 13.1 | 4.5 | | |
| Distributions to non-controlling interest | -52.3 | -36.3 | | | | | | |
| Other | -0.4 | | -0.3 | | | | | |
| Net cash (used) provided by financing activities | 94.6 | 38.8 | 1,385.6 | 14.9 | 24.1 | 166.2 | | |
| Effect of foreign exchange on cash balances | 0.0 | -0.1 | 0.0 | 0.0 | 0.2 | -0.1 | | |
| Change in cash and cash equivalents | 624.7 | 16.5 | 29.4 | 20.1 | 16.9 | 236.7 | | |
| Cash and cash equivalents, beginning of period | 387.2 | 370.8 | 341.4 | 321.3 | 304.4 | 67.7 | | |
| Cash and cash equivalents, end of period | 1,012.0 | 387.2 | 370.8 | 341.4 | 321.3 | 304.4 | | |