Retirement Benefit Plans - Narrative (Details) - USD ($)	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan Disclosure [Line Items]
Number of U.S. Timken retirees			8,400
Payment for Pension Benefits	$ 11,500,000	$ 15,000,000.0	$ 10,800,000
Retirement Benefit Plans (Textual) [Abstract]
Return on plan assets	$ 21,800,000	20,200,000	$ 22,400,000
Company common stock	2,665,260
Fair value of company common stock	$ 131,000,000.0
Canadian Retirees			40
Pension Settlement Charges	0	1,600,000	$ 119,900,000
Professional Fees			2,600,000
Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Actuarial Gain (Loss), Immediate Recognition as Component in Net Periodic Benefit (Cost) Credit	23,200,000	60,900,000	$ 21,100,000
Retirement Benefit Plans (Textual) [Abstract]
Expected long-term return on plan assets			6.00%
Defined Benefit Plan, Plan with Benefit Obligation in Excess of Plan Assets, Benefit Obligation	19,700,000
Defined benefit plans are included in the other non-current assets on the Consolidated Balance Sheets		32,100,000
Current liabilities	6,400,000	5,700,000
Projected benefit obligation	208,800,000
Accumulated benefit obligations	196,100,000
Fair value of plan assets	35,600,000
Pension accumulated benefit obligation	$ 941,500,000	888,000,000.0
Percentage Increase in Value of Pension Assets Due to Investment Performance	10.60%
Expected amortization of prior service cost	$ 1,700,000
Employee Stock [Member]
Retirement Benefit Plans (Textual) [Abstract]
Dividends	3,000,000.0	3,700,000	$ 4,200,000
Domestic Plan [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Actuarial Gain (Loss), Immediate Recognition as Component in Net Periodic Benefit (Cost) Credit	$ (23,100,000)	(41,500,000)	3,400,000
Percentage of Defined Benefit Plan Obligation in US	66.00%
Defined Benefit Plan, Benefit Obligation	$ 643,000,000.0	612,400,000	589,900,000
Retirement Benefit Plans (Textual) [Abstract]
Discount rate to defined pension plans	4.34%
Expected long-term return on plan assets	5.92%
Defined benefit pension plan percentage of fair value of plan assets	65.00%
Current liabilities	$ 4,800,000	$ 4,300,000
Defined Benefit Plan, Benefit Obligation, (Increase) Decrease for Settlement			1,100,000,000
Defined Benefit Plan, Plan Assets, Increase (Decrease) for Assets Transferred to (from) Plan			$ 1,200,000,000
Domestic Plan [Member] | Scenario, Forecast [Member] | Pension Plan [Member]
Retirement Benefit Plans (Textual) [Abstract]
Discount rate to defined pension plans	3.80%
Expected long-term return on plan assets	5.78%
Domestic Plan [Member] | Maximum [Member] | Pension Plan [Member]
Retirement Benefit Plans (Textual) [Abstract]
Discount rate to defined pension plans	4.50%	4.70%	4.64%
Expected long-term return on plan assets	6500000.00%	6.75%
Domestic Plan [Member] | Minimum [Member] | Pension Plan [Member]
Retirement Benefit Plans (Textual) [Abstract]
Discount rate to defined pension plans	4.34%	4.50%	3.98%
Expected long-term return on plan assets	5750000.00%	5.75%
Discount Rate In Dollars [Domain] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Actuarial Gain (Loss), Immediate Recognition as Component in Net Periodic Benefit (Cost) Credit	$ 52,900,000	$ 86,900,000	$ 56,100,000
Other Valuation Assumptions [Domain] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Actuarial Gain (Loss), Immediate Recognition as Component in Net Periodic Benefit (Cost) Credit	8,700,000	10,200,000	22,600,000
Return on Plan Assets vs. Expectation [Domain] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Actuarial Gain (Loss), Immediate Recognition as Component in Net Periodic Benefit (Cost) Credit	38,400,000	36,200,000	57,600,000
Discount Rate In Basis Points [Domain] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Actuarial Gain (Loss), Immediate Recognition as Component in Net Periodic Benefit (Cost) Credit	$ 54		$ 50
Discount Rate In Basis Points [Domain] | UNITED KINGDOM | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Actuarial Gain (Loss), Immediate Recognition as Component in Net Periodic Benefit (Cost) Credit		125
Discount Rate In Basis Points [Domain] | UNITED STATES | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Actuarial Gain (Loss), Immediate Recognition as Component in Net Periodic Benefit (Cost) Credit		$ 36