Lease Agreements (Tables)

12 Months Ended

Dec. 31, 2017

Leases [Abstract]

Future contractual payments under noncancelable leases

Future contractual payments under noncancelable leases for years ended December 31 (which exclude the effect of straight-line rents), are as follows: 

(in thousands)
2018	$	160,025
2019	141,097
2020	120,369
2021	100,766
2022	77,312
Thereafter	245,103
	$	844,672