XML 51 R86.htm IDEA: XBRL DOCUMENT v3.19.3.a.u2
Fair Value Measurements - Assets of Defined Benefit Pension Plans (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2019
Dec. 31, 2018
Dec. 31, 2019
Dec. 31, 2018
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets $ 714,017 $ 649,688 $ 714,017 $ 649,688
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 649,688 708,895    
Actual return on plan assets:        
End of measurement period 714,017 649,688    
U.S.        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 403,144 347,705 403,144 347,705
Other plan liabilities, net     (26,220) 0
Fair value of net plan assets     376,924 347,705
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 347,705      
Actual return on plan assets:        
End of measurement period 403,144 347,705    
U.S. | Quoted Prices in Active Markets (Level 1)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 59,329 40,993 59,329 40,993
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 40,993      
Actual return on plan assets:        
End of measurement period 59,329 40,993    
U.S. | Significant Other Observable Inputs (Level 2)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 329,049 290,224 329,049 290,224
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 290,224      
Actual return on plan assets:        
End of measurement period 329,049 290,224    
U.S. | Significant Unobservable Inputs (Level 3)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 14,766 16,488 14,766 16,488
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 16,488      
Actual return on plan assets:        
End of measurement period 14,766 16,488    
U.S. | Cash and cash equivalents        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 8,082 2,274 8,082 2,274
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 2,274      
Actual return on plan assets:        
End of measurement period 8,082 2,274    
U.S. | Cash and cash equivalents | Quoted Prices in Active Markets (Level 1)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 8,082 2,274 8,082 2,274
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 2,274      
Actual return on plan assets:        
End of measurement period 8,082 2,274    
U.S. | Cash and cash equivalents | Significant Other Observable Inputs (Level 2)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.S. | Cash and cash equivalents | Significant Unobservable Inputs (Level 3)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.S. | Short-term investment funds        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 5,496 5,005 5,496 5,005
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 5,005      
Actual return on plan assets:        
End of measurement period 5,496 5,005    
U.S. | Short-term investment funds | Quoted Prices in Active Markets (Level 1)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.S. | Short-term investment funds | Significant Other Observable Inputs (Level 2)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 5,496 5,005 5,496 5,005
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 5,005      
Actual return on plan assets:        
End of measurement period 5,496 5,005    
U.S. | Short-term investment funds | Significant Unobservable Inputs (Level 3)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.S. | U.S. equity securities        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 60,039 52,882 60,039 52,882
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 52,882      
Actual return on plan assets:        
End of measurement period 60,039 52,882    
U.S. | U.S. equity securities | Quoted Prices in Active Markets (Level 1)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.S. | U.S. equity securities | Significant Other Observable Inputs (Level 2)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 60,039 52,882 60,039 52,882
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 52,882      
Actual return on plan assets:        
End of measurement period 60,039 52,882    
U.S. | U.S. equity securities | Significant Unobservable Inputs (Level 3)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.S. | International equity securities        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 26,142 22,747 26,142 22,747
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 22,747      
Actual return on plan assets:        
End of measurement period 26,142 22,747    
U.S. | International equity securities | Quoted Prices in Active Markets (Level 1)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.S. | International equity securities | Significant Other Observable Inputs (Level 2)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 26,142 22,747 26,142 22,747
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 22,747      
Actual return on plan assets:        
End of measurement period 26,142 22,747    
U.S. | International equity securities | Significant Unobservable Inputs (Level 3)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.S. | U.S. fixed income funds        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 275,994 221,871 275,994 221,871
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 221,871      
Actual return on plan assets:        
End of measurement period 275,994 221,871    
U.S. | U.S. fixed income funds | Quoted Prices in Active Markets (Level 1)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 51,247 38,719 51,247 38,719
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 38,719      
Actual return on plan assets:        
End of measurement period 51,247 38,719    
U.S. | U.S. fixed income funds | Significant Other Observable Inputs (Level 2)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 224,747 183,152 224,747 183,152
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 183,152      
Actual return on plan assets:        
End of measurement period 224,747 183,152    
U.S. | U.S. fixed income funds | Significant Unobservable Inputs (Level 3)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.S. | International fixed income funds        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 3,745 17,523 3,745 17,523
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 17,523      
Actual return on plan assets:        
End of measurement period 3,745 17,523    
U.S. | International fixed income funds | Quoted Prices in Active Markets (Level 1)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.S. | International fixed income funds | Significant Other Observable Inputs (Level 2)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 3,745 17,523 3,745 17,523
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 17,523      
Actual return on plan assets:        
End of measurement period 3,745 17,523    
U.S. | International fixed income funds | Significant Unobservable Inputs (Level 3)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.S. | Alternative strategy funds        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 23,646 25,403 23,646 25,403
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 25,403      
Actual return on plan assets:        
End of measurement period 23,646 25,403    
U.S. | Alternative strategy funds | Quoted Prices in Active Markets (Level 1)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.S. | Alternative strategy funds | Significant Other Observable Inputs (Level 2)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 8,880 8,915 8,880 8,915
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 8,915      
Actual return on plan assets:        
End of measurement period 8,880 8,915    
U.S. | Alternative strategy funds | Significant Unobservable Inputs (Level 3)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 14,766 16,488 14,766 16,488
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 16,488      
Actual return on plan assets:        
End of measurement period 14,766 16,488    
U.S. | Real estate funds | Significant Unobservable Inputs (Level 3)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 14,766 16,488 14,766 16,488
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 16,488 15,134    
Actual return on plan assets:        
Related to assets still held at the reporting date (1,722) 1,354    
End of measurement period 14,766 16,488    
U.K Plan        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 296,943 267,508 296,943 267,508
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 267,508      
Actual return on plan assets:        
End of measurement period 296,943 267,508    
U.K Plan | Quoted Prices in Active Markets (Level 1)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 2,338 3,156 2,338 3,156
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 3,156      
Actual return on plan assets:        
End of measurement period 2,338 3,156    
U.K Plan | Significant Other Observable Inputs (Level 2)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 284,870 254,407 284,870 254,407
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 254,407      
Actual return on plan assets:        
End of measurement period 284,870 254,407    
U.K Plan | Significant Unobservable Inputs (Level 3)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 9,735 9,945 9,735 9,945
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 9,945      
Actual return on plan assets:        
End of measurement period 9,735 9,945    
U.K Plan | Cash and cash equivalents        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 2,338 3,156 2,338 3,156
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 3,156      
Actual return on plan assets:        
End of measurement period 2,338 3,156    
U.K Plan | Cash and cash equivalents | Quoted Prices in Active Markets (Level 1)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 2,338 3,156 2,338 3,156
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 3,156      
Actual return on plan assets:        
End of measurement period 2,338 3,156    
U.K Plan | Cash and cash equivalents | Significant Other Observable Inputs (Level 2)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.K Plan | Cash and cash equivalents | Significant Unobservable Inputs (Level 3)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.K Plan | U.S. equity securities        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 43,613 38,307 43,613 38,307
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 38,307      
Actual return on plan assets:        
End of measurement period 43,613 38,307    
U.K Plan | U.S. equity securities | Quoted Prices in Active Markets (Level 1)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.K Plan | U.S. equity securities | Significant Other Observable Inputs (Level 2)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 43,613 38,307 43,613 38,307
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 38,307      
Actual return on plan assets:        
End of measurement period 43,613 38,307    
U.K Plan | U.S. equity securities | Significant Unobservable Inputs (Level 3)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.K Plan | International equity securities        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 9,418 9,916 9,418 9,916
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 9,916      
Actual return on plan assets:        
End of measurement period 9,418 9,916    
U.K Plan | International equity securities | Quoted Prices in Active Markets (Level 1)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.K Plan | International equity securities | Significant Other Observable Inputs (Level 2)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 9,418 9,916 9,418 9,916
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 9,916      
Actual return on plan assets:        
End of measurement period 9,418 9,916    
U.K Plan | International equity securities | Significant Unobservable Inputs (Level 3)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.K Plan | Short-term Investment funds        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 167,741 160,609 167,741 160,609
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 160,609      
Actual return on plan assets:        
End of measurement period 167,741 160,609    
U.K Plan | Short-term Investment funds | Quoted Prices in Active Markets (Level 1)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.K Plan | Short-term Investment funds | Significant Other Observable Inputs (Level 2)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 167,741 160,609 167,741 160,609
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 160,609      
Actual return on plan assets:        
End of measurement period 167,741 160,609    
U.K Plan | Short-term Investment funds | Significant Unobservable Inputs (Level 3)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.K Plan | Government securities        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 34,926 31,531 34,926 31,531
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 31,531      
Actual return on plan assets:        
End of measurement period 34,926 31,531    
U.K Plan | Government securities | Quoted Prices in Active Markets (Level 1)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.K Plan | Government securities | Significant Other Observable Inputs (Level 2)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 34,926 31,531 34,926 31,531
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 31,531      
Actual return on plan assets:        
End of measurement period 34,926 31,531    
U.K Plan | Government securities | Significant Unobservable Inputs (Level 3)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.K Plan | Alternative strategy funds        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 29,172 14,044 29,172 14,044
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 14,044      
Actual return on plan assets:        
End of measurement period 29,172 14,044    
U.K Plan | Alternative strategy funds | Quoted Prices in Active Markets (Level 1)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.K Plan | Alternative strategy funds | Significant Other Observable Inputs (Level 2)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 29,172 14,044 29,172 14,044
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 14,044      
Actual return on plan assets:        
End of measurement period 29,172 14,044    
U.K Plan | Alternative strategy funds | Significant Unobservable Inputs (Level 3)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.K Plan | Real estate funds        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 9,735 9,945 9,735 9,945
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 9,945      
Actual return on plan assets:        
End of measurement period 9,735 9,945    
U.K Plan | Real estate funds | Quoted Prices in Active Markets (Level 1)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.K Plan | Real estate funds | Significant Other Observable Inputs (Level 2)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 0 0 0 0
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 0      
Actual return on plan assets:        
End of measurement period 0 0    
U.K Plan | Real estate funds | Significant Unobservable Inputs (Level 3)        
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]        
Fair value of plan assets 9,735 9,945 $ 9,735 $ 9,945
Change in fair value of plan assets [Roll Forward]        
Beginning of measurement period 9,945 9,689    
Actual return on plan assets:        
Related to assets still held at the reporting date (210) 256    
End of measurement period $ 9,735 $ 9,945