Employee Benefit Plans and Shareholder Rights Plan - Narrative (Details) $ / shares in Units, $ in Thousands	12 Months Ended
	Dec. 31, 2016 USD ($) $ / shares $ / units	Dec. 31, 2015 USD ($) $ / shares	Dec. 31, 2014 USD ($) $ / shares
Defined Benefit Plan Disclosure [Line Items]
Other Nonoperating Income (Expense)	$ 6,244	$ 15,336	$ 387
Payments Related to Tax Withholding for Share-based Compensation	0
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	(3,004)	247	3,932
US 401K Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized	20,000	22,800	21,300
Foreign Employee Savings Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized	12,100	15,100	18,700
Supplemental Employee Retirement Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Contribution Plan, Cost Recognized	3,300	3,300	3,300
Board of Directors Chairman [Member]
Defined Benefit Plan Disclosure [Line Items]
Other Deferred Compensation Arrangements, Liability, Classified, Noncurrent	4,500	5,100
Trust Value Threshold for Payout to Company	4,000
Norway Member
Defined Benefit Plan Disclosure [Line Items]
Other Nonoperating Income (Expense)	1,100
Foreign Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Benefit Obligation	18,000	28,000
Defined Benefit Plan, Fair Value of Plan Assets	19,000	26,000
Employee Severance [Member]
Defined Benefit Plan Disclosure [Line Items]
Postemployment Benefits, Period Expense		23,100
Deferred Compensation, Excluding Share-based Payments and Retirement Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Deferred Compensation Plan Cash Award Annual Expense	$ (4,200)	$ 6,800	$ 22,800
Deferred Compensation Plan Cash Award Number of Units	437,223
Deferred Compensation, Excluding Share-based Payments and Retirement Benefits [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Deferred Compensation Plan Cash Award Per Unit | $ / units	0
Deferred Compensation, Excluding Share-based Payments and Retirement Benefits [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Deferred Compensation Plan Cash Award Per Unit | $ / units	150
Stock Options [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Expiration Period	7 years
Restricted Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Restricted Stock [Member] | Board of Directors Chairman [Member]
Defined Benefit Plan Disclosure [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Restricted Stock Units (RSUs) [Member]
Defined Benefit Plan Disclosure [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period	3 years
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized	$ 13,300
Employee Service Share-based Compensation, Nonvested Awards, Total Compensation Cost Not yet Recognized, Period for Recognition	1 year 8 months 12 days
Performance Shares [Member] | Minimum [Member]
Defined Benefit Plan Disclosure [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Final Value | $ / shares	$ 0	$ 0	$ 0
Performance Shares [Member] | Maximum [Member]
Defined Benefit Plan Disclosure [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Final Value | $ / shares	$ 150	$ 150	$ 150
Restricted Stock Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Compensation expense	$ 13,900	$ 15,900	$ 17,200
Share-based Compensation Arrangement by Share-based Payment Award, Percentage of Awards Vesting at end of Vesting Period	65.00%	65.00%	60.00%
Stock Compensation Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Excess Tax Benefit (Tax Deficiency) from Share-based Compensation, Financing Activities	$ (3,004)	$ (871)	$ 3,132