Summary of Significant Accounting Policies - Recent Accounting Standards (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	Jan. 01, 2019	Mar. 31, 2018
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
ROU assets	$ 31,411			$ 31,724
Lease liabilities	32,125			$ 32,579
Other expense (income), net	8,975	$ 7,428	$ (3,819)
Retained earnings	1,489,176	1,363,772
Facility Closing [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Curtailment gain		(7,217)	(7,217)
Settlement gain (loss)			(230)
Pensions [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Curtailment gain	0	0	(7,217)
Settlement gain (loss)	$ 340	$ 0	(119)
Pensions [Member] | Facility Closing [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Curtailment gain			(7,217)
Settlement gain (loss)			(230)
Accounting Standards Update 2017-07 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Other expense (income), net			$ (3,827)
Accounting Standards Update 2018-02 [Member]
Revenue, Initial Application Period Cumulative Effect Transition [Line Items]
Retained earnings					$ 19,331