Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Schedule of future minimum lease payments under noncancelable operating leases

As of December 31, 2017, future minimum lease payments under noncancelable operating leases were as follows (in thousands):

Year
2018	$	29,420
2019	24,077
2020	20,113
2021	13,005
2022	9,639
Thereafter	145,214
	$	241,468

Schedule of future commitments to pay for usage of port facilities, marine consumables, services and maintenance contracts

At December 31, 2017, we have future commitments to pay for our usage of certain port facilities, marine consumables, services and maintenance contracts as follows (in thousands):

Year
2018	$	214,444
2019	152,345
2020	130,225
2021	87,748
2022	62,255
Thereafter	232,189
	$	879,206