Commitments, Contingencies and Guarantees (Operating Leases and Other Noncancelable Contractual Obligations) (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Future Minimum Lease Payments
2019	$ 7,251
2020	6,239
2021	5,135
2022	4,775
2023	4,375
Thereafter	12,107
Total	39,882
Other Noncancelable Contracts
2019	46,225
2020	37,566
2021	31,330
2022	30,124
2023	27,849
Thereafter	46,771
Total	219,865
Total
2019	53,476
2020	43,805
2021	36,465
2022	34,899
2023	32,224
Thereafter	58,878
Total	259,747
Future sublease income	632
Total expense recorded under operating leases and other noncancelable contractual obligations	$ 55,200	$ 30,800	$ 20,400