Operating Leases (Tables)

12 Months Ended

Dec. 31, 2017

Leases, Operating [Abstract]

Future minimum lease payments under operating leases

For each of the next five calendar years and thereafter, future minimum lease payments under operating leases that have initial or remaining noncancelable lease terms in excess of one year are as follows:

	Total Payments
2018	$	17,032
2019	14,243
2020	9,330
2021	8,900
2022	2,052
Thereafter	14,953
Total minimum payments	$	66,510