Investment Securities - Available for sale sponsored funds with fair values below carrying values (Details) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2016	Dec. 31, 2015
Fair value
Less than 12 months	$ 9,259
12 months or longer	33,859
Total temporarily impaired securities	43,118
Unrealized losses
Less than 12 months	(222)
12 months or longer	(6,037)
Total Unrealized losses on temporarily impaired securities	(6,259)
Sponsored funds
Fair value
Less than 12 months	2,258	$ 3,476
12 months or longer	33,859	33,619
Total temporarily impaired securities	36,117	37,095
Unrealized losses
Less than 12 months	(44)	(166)
12 months or longer	(6,037)	(6,516)
Total Unrealized losses on temporarily impaired securities	(6,081)	$ (6,682)
Write-off of sponsored funds
Sponsored funds wrote-off	100
Sponsored privately offered funds measured at net asset value
Fair value
Less than 12 months	7,001
Total temporarily impaired securities	7,001
Unrealized losses
Less than 12 months	(178)
Total Unrealized losses on temporarily impaired securities	$ (178)