Annual report pursuant to Section 13 and 15(d)

Benefit Plans - Level 3 Rollforward (Details)

v3.8.0.1
Benefit Plans - Level 3 Rollforward (Details) - Defined Benefit Pension Plans - USD ($)
$ in Thousands
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Defined Benefit Plan Disclosure    
Fair value of plan assets at beginning of period $ 285,060  
Fair value of plan assets at end of the period 314,892 $ 285,060
Significant Unobservable Inputs (Level 3)    
Defined Benefit Plan Disclosure    
Fair value of plan assets at beginning of period 3,286 0
Acquisition (May 4, 2016) 0 3,226
Actual return on plan assets (41) 23
Benefits paid (48) (27)
Contributions 466 236
Exchange rate changes 487 (172)
Fair value of plan assets at end of the period $ 4,150 $ 3,286