Acquisition - Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Jun. 30, 2015	Apr. 01, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Goodwill	$ 216,790		$ 130,976
Cogent Partners, LP
Business Acquisition [Line Items]
Current assets		$ 13,970
Property and equipment		1,214
Other assets		651
Identifiable intangible assets		1,300
Goodwill		92,981
Total assets		110,116
Current liabilities		9,621
Deferred tax liability		500
Total liabilities		10,121
Net assets		$ 99,995