Quarterly report pursuant to Section 13 or 15(d)

Accumulated Other Comprehensive Income - Change by Component (Details)

v3.8.0.1
Accumulated Other Comprehensive Income - Change by Component (Details) - USD ($)
$ in Thousands
 3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax    
Beginning balance $ 1,631,919 $ 1,027,944
Amounts reclassified from accumulated other comprehensive income 9 49
Total other comprehensive income 10,836 13,387
Ending balance 1,647,084 1,040,668
Total    
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax    
Beginning balance 4,311 (53,711)
Other comprehensive income (loss) before reclassifications 9,523 13,922
Amounts reclassified from accumulated other comprehensive income 9 49
Total other comprehensive income 9,532 13,971
Ending balance 13,843 (39,740)
Defined benefit and other postretirement plans    
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax    
Beginning balance 7,412 7,513
Other comprehensive income (loss) before reclassifications (32) (214)
Amounts reclassified from accumulated other comprehensive income 14 33
Total other comprehensive income (18) (181)
Ending balance 7,394 7,332
Net gain (loss) from hedging activities    
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax    
Beginning balance 967 4,557
Other comprehensive income (loss) before reclassifications 2,188 (1,785)
Amounts reclassified from accumulated other comprehensive income (5) 16
Total other comprehensive income 2,183 (1,769)
Ending balance 3,150 2,788
Foreign currency translation    
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax    
Beginning balance (4,068) (65,781)
Other comprehensive income (loss) before reclassifications 7,367 15,921
Amounts reclassified from accumulated other comprehensive income 0 0
Total other comprehensive income 7,367 15,921
Ending balance $ 3,299 $ (49,860)