Acquisition (Details) (USD $)	0 Months Ended	3 Months Ended		0 Months Ended
	Mar. 16, 2015	Mar. 31, 2015	Mar. 31, 2014	Mar. 31, 2015	Dec. 31, 2014
Acquisitions
Cash purchase price excluding transaction fees and expenses	$ 30,200,000
Contingent consideration		17,940,000		17,940,000
Recognized amounts of tangible assets and liabilities:
Goodwill (including deferred tax adjustment of $2,134		440,008,000		440,008,000	398,164,000
Amortization of intangible assets		41,000	6,000
3Q Digital Inc
Total consideration
Cash consideration per purchase agreement	30,245,000
Estimated fair value of contingent consideration	17,940,000
Fair value of total consideration transferred	48,185,000
Recognized amounts of tangible assets and liabilities:
Current assets	4,135,000
Property and equipment	164,000
Other assets	389,000
Current liabilities	(822,000)
Total tangible assets and liabilities:	3,866,000
Identifiable intangible assets	4,773,000
Goodwill (including deferred tax adjustment of $2,134	41,844,000
Total	50,483,000
Deferred tax adjustment	2,298,000
3Q Digital Inc | Customer relationships
Recognized amounts of tangible assets and liabilities:
Amortization of intangible assets				4,300,000
Amortization period				7 years
3Q Digital Inc | Tradenames and trademarks
Recognized amounts of tangible assets and liabilities:
Amortization of intangible assets				300,000
Amortization period				2 years
3Q Digital Inc | Non-compete agreements
Recognized amounts of tangible assets and liabilities:
Amortization of intangible assets				200,000
Amortization period				3 years
Minimum | 3Q Digital Inc
Acquisitions
Contingent consideration	0
Maximum | 3Q Digital Inc
Acquisitions
Contingent consideration	$ 35,000,000