Unconditional Purchase Obligations (Tables)

12 Months Ended

Dec. 31, 2017

Unconditional Purchase Obligations (Excluding Capital Stock Redemptions) [Abstract]

Unrecorded Unconditional Purchase Obligations Disclosure

Future expenditures under unconditional purchase obligations in effect as of December 31, 2017 are as follows:

(in thousands)
2018	$	22,408
2019	18,271
2020	6,706
2021	4,545
2022	—
Total	$	51,930