CONSOLIDATED STATEMENTS OF CASH FLOWS (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
OPERATING ACTIVITIES:
Net income	$ 41,204	$ 27,989	$ 65,669
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	52,611	50,172	39,172
Deferred income tax provision (benefit)	1,537	1,156	4,128
Share-based compensation	9,051	26,805	17,209
Amortization of debt issuance costs	2,725	3,387	1,490
Non-cash interest expense	8,520	10,591	7,125
Payment of accreted interest	(30,617)	0	(6,599)
Loss on disposal of property and equipment	1,312	0	0
Excess tax benefits from stock-based compensation arrangements	(3,634)	(848)	(3,580)
Other, net		164	(3)
Changes in assets and liabilities, net of business acquisitions:
Accounts receivable	3,783	(1,878)	(3,783)
Inventories	(711)	1,702	(7,374)
Prepaid expenses and other current assets	(3,067)	(395)	(6,452)
Other non-current assets	(938)	375	(179)
Accounts payable, accrued expenses and other current liabilities	(21,071)	(11,842)	6,736
Deferred revenue	(1,051)	104	(457)
Other non-current liabilities	(939)	(3,154)	(7,531)
Net cash provided by operating activities	58,715	104,328	105,571
INVESTING ACTIVITIES:
Cash used in business acquisition, net of cash acquired	(7,278)	(151,951)	(5,178)
Purchases of property and equipment	(69,031)	(38,425)	(37,138)
Purchases of short-term investments	(67,907)	0	0
Maturities of short-term investments	64,940	0	0
Net cash used in investing activities	(79,276)	(190,376)	(42,316)
FINANCING ACTIVITIES:
Borrowings under senior credit facility	155,000	145,000	105,000
Repayments under senior credit facility	(12,812)	(213,437)	(16,875)
Proceeds from liability component of convertible notes	0	186,830	0
Proceeds from equity component of convertible notes	0	43,170	0
Proceeds from sale of stock purchase warrants	0	28,451	0
Purchase of option hedge on convertible notes	0	(42,895)	0
Payment of liability component of convertible notes	(134,383)	0	(71,351)
Debt issuance costs	0	(8,064)	(6,796)
Purchases of treasury stock	0	(83,463)	(31,278)
Proceeds from exercised stock options	696	3,697	16,146
Excess tax benefits from stock-based compensation arrangements	3,634	848	3,580
Net cash provided by (used in) financing activities	12,135	60,137	(1,574)
Effect of exchange rate changes on cash and cash equivalents	4,556	(2,044)	(4,809)
Net increase (decrease) in cash and cash equivalents	(3,870)	(27,955)	56,872
Cash and cash equivalents at beginning of period	100,808	128,763	71,891
Cash and cash equivalents at end of period	$ 96,938	$ 100,808	$ 128,763