Income Taxes - Effective Tax Rate Reconciliation (Details) - USD ($)	3 Months Ended			12 Months Ended			13 Months Ended
	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Jun. 30, 2017
Difference between the effective income tax provision rate and the U.S. federal statutory income tax provision rate
U.S. federal statutory income tax rate (as a percent)				21.00%	21.00%	35.00%
U.S. state income taxes, net of federal income tax benefit (as a percent)				1.40%	(1.00%)	1.90%
Foreign tax rate differences (as a percent)				3.60%	6.80%	(3.40%)
Tax on foreign dividends (as a percent)				0.009	0.036	(0.003)
Foreign financing structure (as a percent)				(3.00%)	(5.10%)	(2.20%)
Change in statutory rates (as a percent)				0.00%	(3.90%)	(10.60%)
Research and development and other tax credits (as a percent)				(6.20%)	(10.50%)	(3.30%)
Excess tax benefits from stock compensation (as a percent)				(0.20%)	(2.90%)	(4.90%)
Uncertain income tax positions (as a percent)				(1.90%)	2.00%	0.80%
Other differences - net (as a percent)				1.10%	(0.50%)	(0.60%)
Effective income tax rate (as a percent)				16.70%	9.50%	12.40%
Difference between the effective income tax provision and the U.S. federal statutory income tax provision
U.S. federal statutory income tax rate				$ 14,000,000.0	$ 8,600,000	$ 32,100,000
U.S. state income taxes, net of federal income tax benefit				900,000	(400,000)	1,700,000
Foreign tax rate differences				2,400,000	2,800,000	(3,100,000)
Tax on foreign dividends				600,000	1,500,000	(300,000)
Foreign financing structure				(2,000,000.0)	(2,100,000)	(2,000,000.0)
Change in statutory tax rate, amount				0	1,600,000	9,700,000
Research and development and other tax credits				(4,100,000)	(4,300,000)	(3,000,000.0)
Excess tax benefits from stock compensation				(100,000)	(1,200,000)	(4,500,000)
Uncertain income tax positions				(1,300,000)	800,000	700,000
Other differences, net				700,000	(200,000)	(500,000)
Total provision for income taxes				11,100,000	3,900,000	11,400,000
Transition tax for accumulated foreign earnings, income tax expense (benefit)						3,800,000	$ 4,600,000
Measurement period adjustment to transition tax					800,000
Change in tax rate effect on deferred taxes						10,300,000	$ 11,200,000
Measurement period tax benefit adjustment					(900,000)
Impairment loss	$ (2,900,000)	$ 2,000,000.0	$ 32,000,000.0	$ 0	31,100,000	0
Federal Ministry of Finance, Germany
Difference between the effective income tax provision and the U.S. federal statutory income tax provision
Change in statutory tax rate, amount						(600,000)
Interest limitation						$ 4,100,000		$ 4,100,000
Disposal Group, Held-for-sale or Disposed of by Sale, Not Discontinued Operations | Brattleboro Mill and Associated Research and Office Facilities
Difference between the effective income tax provision and the U.S. federal statutory income tax provision
Impairment loss					31,100,000
Netherlands
Difference between the effective income tax provision and the U.S. federal statutory income tax provision
Change in statutory tax rate, amount	$ 700,000				$ 700,000