Commitments and Contingencies (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Minimum Future Rental Payments under Operating Leases

Minimum future rental payments under these leases are as set forth below for each of the following years (dollars in thousands):

2018	$	42,483
2019	31,975
2020	26,792
2021	22,149
2022	17,958
Thereafter	47,850
	$	189,207