Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies [Abstract]

Future minimum lease payments for operating leases

Future minimum lease payments for operating leases with initial or remaining noncancelable lease terms in excess of one year are as follows:

2018	$	19,773
2019		14,360
2020		11,082
2021		8,499
2022		6,634
Thereafter		20,478