Contingencies, Commitments and Guarantees (Tables)

12 Months Ended

Dec. 31, 2017

Commitments and Contingencies Disclosure [Abstract]

Schedule of aggregate minimum lease commitments under operating leases

The Company leases office space throughout the United States and in a limited number of foreign countries where the Company's international operations reside. Aggregate minimum lease commitments under operating leases as of December 31, 2017 are as follows:

(Dollars in thousands)
2018	$	14,509
2019	12,884
2020	12,214
2021	7,888
2022	6,544
Thereafter	14,872
Total	$	68,911