Acquisitions - Narrative (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
	Jan. 01, 2015	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
J.P. Morgan Retirement Plan Services (RPS)
Business Acquisition [Line Items]
Revenue of acquired entity from date of acquisition		$ 42,260	$ 14,261	$ 137,206	$ 14,261
Net income of acquired entity from date of acquisition		$ (1,061)	$ 494	$ 237	$ 494
Putnam Retirement Business
Business Acquisition [Line Items]
Cash paid	$ 4,114
Other assets acquired	11,501
Other liabilities assumed	7,895
Dividend	$ 508