Consolidated Statements of Cash Flows (USD $)
In Thousands, unless otherwise specified
3 Months Ended
Mar. 31, 2015
Mar. 31, 2014
Cash flows from operating activities:    
Net income $ 99,554 $ 77,345
Items not involving cash:    
Stock-based compensation 8,789 6,828
Depreciation of property and equipment 16,789 13,359
Amortization of intangible assets 52,619 54,986
Deferred lease inducements and rent (6,723) (77)
Deferred income taxes 3,836 (12,334)
Tax benefit on option exercises (1,916) (2,692)
Deferred financing cost amortization 2,469 2,188
Changes in operating assets and liabilities, net of effects from acquisitions:    
Accounts receivable (82,210) (171,907)
Rebates receivable 29,168 (362,352)
Other current assets 22,114 26,310
Accounts payable 71,948 144,264
Accrued expenses and other current liabilities (59,196) 20,753
Rebates payable (12,110) 362,635
Other long-term assets and liabilities 1,551 (23,630)
Net cash provided by operating activities 146,682 135,676
Cash flows from investing activities:    
Acquisition, net of cash acquired (261,668) (2,026)
Purchases of property and equipment (9,140) (12,782)
Net cash used by investing activities (270,808) (14,808)
Cash flows from financing activities:    
Proceeds from issuance of debt 0 492,500
Repayment of long-term debt (12,500) (306,250)
Payment of financing costs 0 (955)
Proceeds from exercise of options 28 3,567
Tax benefit on option exercises 1,916 2,692
Distributions to non-controlling interest (12,087) (15,000)
Other (28) 0
Net cash (used) provided by financing activities (22,671) 176,554
Effect of foreign exchange on cash balances 46 52
Change in cash and cash equivalents (146,751) 297,474
Cash and cash equivalents, beginning of period 1,011,952 387,241
Cash and cash equivalents, end of period $ 865,201 $ 684,715