Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands			9 Months Ended		12 Months Ended
	Oct. 01, 2018	Feb. 28, 2018	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017	Jul. 30, 2018	Jan. 01, 2018
Summary Of Significant Accounting Policies [Line Items]
Aggregate amount of transaction price allocated to remaining performance obligations			$ 527,000
Remaining performance obligations expected to be recognized, year			2028
Restricted cash			$ 3,000		$ 4,200
Proceeds from sale/maturity of short-term investments			190,467	$ 150,768
Short-term investments			2,130		$ 139,117
Business acquisition, net of cash acquired			$ 71,443
Equity method investments						$ 2,000
Equity method investment, include direct cost						$ 2,800
Payment Technology and Services Company
Summary Of Significant Accounting Policies [Line Items]
Equity method investment, noncontrolling financial interest						4.00%
Business Ink
Summary Of Significant Accounting Policies [Line Items]
Business acquisition date			Feb. 28, 2018
Business acquisition, net of cash acquired		$ 70,000
Forte Payment Systems, Inc
Summary Of Significant Accounting Policies [Line Items]
Business acquisition date			Oct. 01, 2018
Forte Payment Systems, Inc | Subsequent Event
Summary Of Significant Accounting Policies [Line Items]
Business acquisition, net of cash acquired	$ 80,000
Business acquisition, cash consideration	85,000
Cash held subject to certain tax filings	$ 13,000
Maximum
Summary Of Significant Accounting Policies [Line Items]
Billed accounts receivable, payment term			60 days
Short-term investment contractual maturities			2 years		2 years
Minimum
Summary Of Significant Accounting Policies [Line Items]
Billed accounts receivable, payment term			30 days
Cloud and Related Solutions Revenue | Maximum
Summary Of Significant Accounting Policies [Line Items]
Long-term arrangements service period			5 years
Future revenue including variable consideration, contractual terms ending, year			2028
Cloud and Related Solutions Revenue | Minimum
Summary Of Significant Accounting Policies [Line Items]
Long-term arrangements service period			3 years
Future revenue including variable consideration, contractual terms ending, year			2019
ASC 606
Summary Of Significant Accounting Policies [Line Items]
Cumulative effect upon adoption of new accounting principle, increase in retained earnings net of tax							$ 7,000