CONDENSED CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
OPERATING ACTIVITIES:
Net income	$ 28,418	$ 23,429
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	39,122	37,303
Deferred income tax provision (benefit)	(3,184)	(4,450)
Amortization of debt issuance costs	2,103	2,630
Non-cash interest expense	8,284	7,119
Payment of accreted interest	(30,617)	0
Loss on disposal of property and equipment	807	0
Share-based compensation	6,632	18,897
Excess tax benefits from stock-based compensation arrangements	(432)	(844)
Changes in assets and liabilities, net of business acquisitions:
Accounts receivable	(1,333)	(777)
Inventories	1,080	(6,788)
Prepaid expenses and other current assets	8,148	(546)
Other non-current assets	(877)	(61)
Accounts payable, accrued expenses and other current liabilities	6,528	(4,185)
Deferred revenue	(913)	(816)
Other non-current liabilities	(1,263)	(1,278)
Net cash provided by operating activities	62,503	69,633
INVESTING ACTIVITIES:
Purchases of property and equipment	(44,359)	(25,381)
Cash used in business acquisition	(2,177)	(149,420)
Purchases of short-term investments	(67,907)	0
Maturities of short-term investments	64,940	0
Net cash used in investing activities	(49,503)	(174,801)
FINANCING ACTIVITIES:
Borrowings under senior credit facility	155,000	135,000
Repayments under senior credit facility	(12,812)	(190,625)
Proceeds from liability component of convertible notes	0	186,830
Proceeds from equity component of convertible notes	0	43,170
Proceeds from sale of stock purchase warrants	0	28,451
Payment of liability component of convertible notes	(134,383)	0
Purchase of option hedge on convertible notes	0	(42,895)
Debt issuance costs	0	(8,064)
Purchases of treasury stock	0	(69,011)
Proceeds from exercised stock options	696	3,544
Excess tax benefits from stock-based compensation arrangements	432	844
Net cash provided by (used in) financing activities	8,933	87,244
Effect of exchange rate changes on cash and cash equivalents	2,977	152
Net change in cash and cash equivalents	24,910	(17,772)
Cash and cash equivalents at beginning of period	100,808	128,763
Cash and cash equivalents at end of period	$ 125,718	$ 110,991