Annual report pursuant to Section 13 and 15(d)

Benefit Plans - Net Periodic Pension Expense Benefit (Details)

v3.10.0.1
Benefit Plans - Net Periodic Pension Expense Benefit (Details) - USD ($)
 12 Months Ended
Dec. 31, 2018
Dec. 31, 2017
Dec. 31, 2016
Defined Benefit Pension Plans | U.S.      
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)      
Service cost $ 1,019,000 $ 1,219,000 $ 2,130,000
Interest cost 9,599,000 10,115,000 7,680,000
Expected return on plan assets (12,851,000) (12,277,000) (9,293,000)
Amortization of net gain 0 0 0
Curtailment gain recognized (576,000) 0 (1,311,000)
Settlement (gain) loss recognized 0 (48,000) 152,000
Net periodic expense (benefit) (2,809,000) (991,000) (642,000)
Defined Benefit Pension Plans | Foreign      
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)      
Service cost 3,566,000 3,686,000 2,106,000
Interest cost 3,340,000 3,271,000 2,224,000
Expected return on plan assets (3,311,000) (3,208,000) (2,038,000)
Amortization of net gain 49,000 (9,000) (10,000)
Curtailment gain recognized (340,000) 0 (517,000)
Settlement (gain) loss recognized (11,000) 0 0
Net periodic expense (benefit) 3,293,000 3,740,000 1,765,000
Supplemental Retirement Plans      
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)      
Interest cost 450,000 489,000 328,000
Net periodic expense (benefit) 450,000 489,000 328,000
Estimated amortization of actuarial gain for next fiscal period 0    
Other Postretirement Benefits Plans      
Defined Benefit Plan, Net Periodic Benefit Cost (Credit)      
Service cost 16,000 21,000 37,000
Interest cost 150,000 174,000 151,000
Amortization of prior service credit (112,000) (78,000) 0
Amortization of net gain (26,000) (45,000) (17,000)
Net periodic expense (benefit) 28,000 $ 72,000 $ 171,000
Estimated amortization of actuarial gain for next fiscal period 32,000    
Estimated amortization of prior service credit for next fiscal period $ 130,000