Acquisitions - Summary of the Estimated Fair Value of the Tangible and Intangible Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Thousands	Aug. 05, 2015	Jun. 11, 2015	Sep. 22, 2014	Sep. 03, 2014	Sep. 30, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Goodwill					$ 40,778	$ 8,366
REV
Business Acquisition [Line Items]
Cash and cash equivalents				$ 765
Accounts receivable				1,753
Property and equipment				289
Identifiable intangibles				1,019
Other assets				16
Total assets acquired				3,842
Total liabilities assumed				655
Net assets acquired and net liabilities assumed				3,187
Goodwill				2,756
Total purchase price				$ 5,943
LAL
Business Acquisition [Line Items]
Cash and cash equivalents			$ 30
Accounts receivable			1,299
Property and equipment			253
Identifiable intangibles			1,290
Other assets			28
Total assets acquired			2,900
Total liabilities assumed			1,617
Net assets acquired and net liabilities assumed			1,283
Goodwill			5,610
Total purchase price			$ 6,893
Moda
Business Acquisition [Line Items]
Cash and cash equivalents		$ 126
Accounts receivable		335
Property and equipment		27
Identifiable intangibles		300
Other assets		23
Total assets acquired		811
Total liabilities assumed		542
Net assets acquired and net liabilities assumed		269
Goodwill		1,439
Total purchase price		$ 1,708
Cross View, Inc.
Business Acquisition [Line Items]
Accounts receivable	$ 7,698				$ 1,200
Property and equipment	336
Identifiable intangibles	11,850
Other assets	254
Total assets acquired	20,138
Total liabilities assumed	2,404
Net assets acquired and net liabilities assumed	17,734
Goodwill	30,973
Total purchase price	$ 48,707