Fair Value Measurements Classes of Financial Assets and Liabilities Measured at Fair Value on Recurring Basis (Details) - USD ($) $ in Thousands		Dec. 31, 2017	Dec. 31, 2016
Cash and cash equivalents		$ 316,264	$ 104,839
NAV Practical Expedient		111,202	83,096
Available-for-sale equity securities		1,579	130,785
Trading securities—equity		9,457	20,059
Trading securities—debt		42,238	45,466
Other assets	[1]	1,240	859
Total financial assets		370,778	302,008
Total financial liabilities	[2]	1,203	2,291
Level 1 [Member]
Cash and cash equivalents		205,364	54,725
Available-for-sale equity securities		1,406	103,996
Trading securities—equity		8,582	13,866
Trading securities—debt		0	0
Other assets	[1]	123	19
Total financial assets		215,475	172,606
Total financial liabilities	[2]	0	2
Level 2 [Member]
Cash and cash equivalents		0	0
Available-for-sale equity securities		0	0
Trading securities—equity		746	0
Trading securities—debt		42,238	45,466
Other assets	[1]	357	0
Total financial assets		43,341	45,466
Total financial liabilities	[2]	0	358
Level 3 [Member]
Cash and cash equivalents		0	0
Available-for-sale equity securities		0	0
Trading securities—equity		0	0
Trading securities—debt		0	0
Other assets	[1]	760	840
Total financial assets		760	840
Total financial liabilities	[2]	1,203	1,931
Cash and Cash Equivalents [Member]
NAV Practical Expedient		110,900	50,114
Available-for-sale Securities [Member]
NAV Practical Expedient		173	26,789
Trading Securities [Member]
NAV Practical Expedient		$ 129	$ 6,193

[1] Amounts include structured trade finance loans held by Federated as well as futures contracts and/or foreign currency forward contracts held within certain consolidated Federated Funds.

[2] Amounts include acquisition-related future consideration liabilities as well as certain liabilities attributable to structured trade finance loans held by Federated and may include foreign currency forward contracts and/or futures contracts held within certain consolidated Federated Funds.