Consolidated Balance Sheets - USD ($) $ in Thousands	Jun. 30, 2018	Dec. 31, 2017
Current assets:
Cash and cash equivalents	$ 742,204	$ 642,319
Investments	1,506,289	2,751,382
Accounts receivable, net	492,826	533,825
Inventories	299,595	270,294
Other current assets	83,086	72,314
Total current assets	3,124,000	4,270,134
Property, plant and equipment, net	335,709	349,278
Intangible assets, net	218,175	228,395
Goodwill	357,507	359,819
Other assets	122,353	116,728
Total assets	4,157,744	5,324,354
Current liabilities:
Notes payable and debt	499	100,273
Accounts payable	71,190	64,537
Accrued employee compensation	36,729	69,024
Deferred revenue and customer advances	203,715	166,840
Accrued income taxes	64,425	73,008
Accrued warranty	12,499	13,026
Other current liabilities	85,860	119,449
Total current liabilities	474,917	606,157
Long-term liabilities:
Long-term debt	1,147,951	1,897,501
Long-term portion of retirement benefits	67,634	67,334
Long-term income tax liabilities	417,267	456,949
Other long-term liabilities	74,881	62,625
Total long-term liabilities	1,707,733	2,484,409
Total liabilities	2,182,650	3,090,566
Commitments and contingencies (Notes 6, 7 and 11)
Stockholders' equity:
Preferred stock, par value $0.01 per share, 5,000 shares authorized, none issued at June 30, 2018 and December 31, 2017
Common stock, par value $0.01 per share, 400,000 shares authorized, 160,298 and 159,845 shares issued, 77,032 and 79,337 shares outstanding at June 30, and December 31, 2017, respectively	1,603	1,598
Additional paid-in capital	1,798,708	1,745,088
Retained earnings	5,669,039	5,405,380
Treasury stock, at cost, 83,266 and 80,509 shares at June 30, 2018 and December 31, 2017, respectively	(5,361,355)	(4,808,211)
Accumulated other comprehensive loss	(132,901)	(110,067)
Total stockholders' equity	1,975,094	2,233,788
Total liabilities and stockholders' equity	$ 4,157,744	$ 5,324,354

Carrying value as of the balance sheet date of liabilities incurred (and for which invoices have typically been received) and payable to vendors for goods and services received that are used in an entity's business. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

Name:	us-gaap_AccountsPayableCurrent
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount due from customers or clients, within one year of the balance sheet date (or the normal operating cycle, whichever is longer), for goods or services (including trade receivables) that have been delivered or sold in the normal course of business, reduced to the estimated net realizable fair value by an allowance established by the entity of the amount it deems uncertain of collection.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 50
-Paragraph 8
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=109196051&loc=SL49130549-203045

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(3))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682