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Retirement Plans (Narrative) (Details) $ in Thousands	9 Months Ended
	Sep. 30, 2019 USD ($) plan
Defined Benefit Plan Disclosure
Defined contribution plan number	6
United States
Defined Benefit Plan Disclosure
Number of retirement plans	3
Number of defined benefit plans	1
Defined contribution plan number	2
Defined benefit plans, estimated future employer contributions in current fiscal year | $	$ 550
Canada
Defined Benefit Plan Disclosure
Defined contribution plan number	2
United Kingdom
Defined Benefit Plan Disclosure
Defined contribution plan number	2
Defined benefit plans, estimated future employer contributions in current fiscal year | $	$ 241
Defined benefit plan, contributions by employer | $	$ 187

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