Business Acquisitions - Dealflo Limited (Details) - USD ($) $ in Thousands		3 Months Ended								12 Months Ended
	May 30, 2018	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017	May 29, 2018	Jan. 01, 2018
Acquired Finite-Lived Intangible Assets
Acquired identifiable intangible assets, Estimated Fair Value	$ 17,900
Goodwill.		$ 94,612				$ 91,841				$ 94,612	$ 91,841	$ 56,332
Net losses		$ (5,050)	$ (11,872)	$ 2,461	$ 5,671	$ (3,964)	$ 908	$ 1,002	$ (1,792)	(8,789)	(3,846)	$ 22,399
Dealflo Limited
Acquired Finite-Lived Intangible Assets
Ownership percentage	100.00%
Cash	$ 5,700
Cash paid to acquire remaining interest	$ 53,100
Remaining ownership percentage acquired	99.00%
Fair value of previous ownership interest	$ 800									800
Previous ownership percentage													1.00%
Increase in deferred tax liability										1,800
Increase in other current assets										600
Increase in goodwill										$ 1,100
Increase in book value of ownership interest														$ 500
Acquired tangible assets	2,700
Acquired identifiable intangible assets, Estimated Fair Value	17,900
Liabilities assumed	(6,041)
Goodwill.	39,295
Total purchase price consideration	53,854
Acquisition related expense											$ 1,100
Customer relationships
Acquired Finite-Lived Intangible Assets
Acquired identifiable intangible assets, Estimated Fair Value	$ 11,800
Identifiable Intangible Assets, Estimated Weighted Average Amortization Period	7 years
Technology
Acquired Finite-Lived Intangible Assets
Acquired identifiable intangible assets, Estimated Fair Value	$ 5,900
Identifiable Intangible Assets, Estimated Weighted Average Amortization Period	4 years
Trademarks
Acquired Finite-Lived Intangible Assets
Acquired identifiable intangible assets, Estimated Fair Value	$ 200
Identifiable Intangible Assets, Estimated Weighted Average Amortization Period	3 years