Consolidated Statement of Cash Flows (Details) - USD ($) $ in Thousands	12 Months Ended
Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
(Increase) decrease in:
Accounts and notes receivable, net	$ 190,141	$ (336,109)	$ (98,744)
Contract work in progress	80,742	50,570	101,158
Other current assets	(13,191)	28,482	102,417
Other assets	(62,396)	44,580	(26,204)
Increase (decrease) in:
Trade accounts payable	(57,317)	(153,515)	(274,418)
Advance billings on contracts	243,996	(63,594)	(29,043)
Accrued liabilities	(38,529)	31,697	(83,613)
Other liabilities	(39,550)	(10,972)	46,851
Increase (decrease) in cash due to changes in operating assets and liabilities	303,896	(408,861)	(261,596)
Cash paid during the year for:
Interest	40,585	23,509	22,585
Income taxes payments, net of refunds	$ 249,921	$ 228,471	$ 268,889

The amount of cash paid during the current period to foreign, federal, state, and local authorities as taxes on income, net of any cash received during the current period as refunds for the overpayment of taxes.

Name:	us-gaap_IncomeTaxesPaidNet
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The increase (decrease) during the reporting period of the sum of amounts due within one year (or one business cycle) from customers for the credit sale of goods and services; and from note holders for outstanding loans.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 28
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3602-108585

+ Details

Name:	us-gaap_IncreaseDecreaseInAccountsAndNotesReceivable
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Change in recurring obligations of a business that arise from the acquisition of merchandise, materials, supplies and services used in the production and sale of goods and services.

+ References

+ Details

Name:	us-gaap_IncreaseDecreaseInAccountsPayableTrade
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The increase (decrease) during the reporting period in the aggregate amount of expenses incurred but not yet paid.

+ References

+ Details

Name:	us-gaap_IncreaseDecreaseInAccruedLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The increase (decrease) during the reporting period in the amount of prepayments by customers for goods or services to be provided at a later date.

+ References

+ Details

Name:	us-gaap_IncreaseDecreaseInCustomerAdvances
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_IncreaseDecreaseInOperatingAssetsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The increase (decrease) during the reporting period of all assets and liabilities used in operating activities.

+ References

+ Details

Name:	us-gaap_IncreaseDecreaseInOperatingCapital
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_IncreaseDecreaseInOperatingLiabilitiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The increase (decrease) during the reporting period in other current operating assets not separately disclosed in the statement of cash flows.

+ References

No definition available.

+ Details

Name:	us-gaap_IncreaseDecreaseInOtherCurrentAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The increase (decrease) during the reporting period in other assets used in operating activities not separately disclosed in the statement of cash flows. May include changes in other current assets, other noncurrent assets, or a combination of other current and noncurrent assets.

+ References

+ Details

Name:	us-gaap_IncreaseDecreaseInOtherOperatingAssets
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The increase (decrease) during the reporting period in other liabilities used in operating activities not separately disclosed in the statement of cash flows. May include changes in other current liabilities, other noncurrent liabilities, or a combination of other current and noncurrent liabilities.

+ References

+ Details

Name:	us-gaap_IncreaseDecreaseInOtherOperatingLiabilities
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

The increase (decrease) during the reporting period of the amount of revenue for work performed for which billing has not occurred, net of uncollectible accounts.

+ References

+ Details

Name:	us-gaap_IncreaseDecreaseInUnbilledReceivables
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The amount of cash paid for interest during the period.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=6367179&loc=d3e4297-108586

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 25
-Subparagraph (e)
-URI http://asc.fasb.org/extlink&oid=56944662&loc=d3e3536-108585

+ Details

Name:	us-gaap_InterestPaid
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_PaymentsForOperatingActivitiesAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration