Condensed Consolidated Balance Sheets (Unaudited) - USD ($) $ in Thousands	Sep. 30, 2017	Dec. 31, 2016
Current Assets:
Cash and cash equivalents	$ 678,284	$ 465,232
Short-term investments	4,135	3,057
Receivables, net	170,312	157,171
Inventories	36,000	39,475
Prepaid expenses and other	42,374	37,099
Total current assets	931,105	702,034
Property, plant and equipment, net of accumulated depreciation of $648,298 and $612,961, respectively	244,620	238,607
Goodwill	574,912	572,764
Acquired intangibles, net of accumulated amortization of $283,632 and $267,723, respectively	216,177	258,814
Long-term receivables	11,590	12,949
Other assets	326,823	311,740
Total assets	2,305,227	2,096,908
Current Liabilities:
Revolving credit facility	0	50,000
Accounts payable and accrued liabilities	199,672	239,496
Current portion of deferred revenue	320,462	296,066
Total current liabilities	520,134	585,562
Long-Term Liabilities:
Long-term portion of deferred revenue	57,865	66,769
Long-term debt	644,146	643,493
Other long-term liabilities	72,342	59,314
Total long-term liabilities	774,353	769,576
Commitments and contingencies
Stockholders' Equity:
Common stock and capital in excess of par value	1,807,839	1,820,081
Treasury stock, at cost	(1,142,524)	(1,190,053)
Retained earnings	355,445	136,902
Accumulated other comprehensive loss	(10,020)	(25,160)
Total stockholders’ equity	1,010,740	741,770
Total liabilities and stockholders’ equity	$ 2,305,227	$ 2,096,908