Unaudited Quarterly Financial Data (Details Textual) - USD ($) $ / shares in Units, $ in Thousands, shares in Millions	1 Months Ended	3 Months Ended								12 Months Ended
	Jan. 31, 2017	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
Quarterly Financial Information
Restructuring and reorganization charges		$ 1,600	$ 1,300	$ 1,800		$ 1,600	$ 2,800	$ 3,300	$ 900	$ 4,834	$ 8,661	$ 8,796
Impact of restructuring and reorganization charges on EPS		$ 0.04	$ 0.03	$ 0.04		$ 0.04	$ 0.07	$ 0.07	$ 0.02
Effective income tax rate		7.00%	25.00%	28.00%	26.00%	18.00%	21.00%	27.00%	31.00%
Income tax benefit		$ (1,633)	$ (7,262)	$ (7,458)	$ (6,600)	$ (4,669)	$ (4,391)	$ (5,607)	$ (6,190)	$ (22,953)	(20,857)	$ (26,346)
Comcast
Quarterly Financial Information
Income tax benefit		$ 4,000
Stock warrants exercised	1.4	0.4								0.4
Business Ink and Forte
Quarterly Financial Information
Transaction related cost					$ 1,300	$ 2,300	$ 200		$ 2,400		$ 2,300
Impact of transaction related cost on EPS					$ 0.03	$ 0.06	$ 0.01		$ 0.05