Acquisitions - Schedule of Business Acquisition, By Acquisition (Details) - USD ($) $ in Thousands	Jan. 02, 2018	Mar. 31, 2018	Dec. 31, 2017
Business Acquisition [Line Items]
Goodwill		$ 154,590	$ 144,835
Hula Partners [Member]
Business Acquisition [Line Items]
Cash purchase price	$ 10,000
Goodwill	8,527
Total assets	10,000
Customer relationships | Hula Partners [Member]
Business Acquisition [Line Items]
Intangible assets, other than goodwill	$ 1,367
Acquired finite-lived intangible assets, weighted average useful life	4 years
Marketing-Related Intangible Assets | Hula Partners [Member]
Business Acquisition [Line Items]
Intangible assets, other than goodwill	$ 106
Acquired finite-lived intangible assets, weighted average useful life	2 years