Summary of Significant Accounting Policies (Details Textual) - USD ($) $ in Thousands	3 Months Ended		12 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2018	Jan. 01, 2019
Summary Of Significant Accounting Policies [Line Items]
Aggregate amount of transaction price allocated to remaining performance obligations	$ 532,000
Remaining performance obligations expected to be recognized, year	2028
Deferred revenue recognized	$ 18,500
Restricted cash	3,000		$ 3,000
Proceeds from sale/maturity of short-term investments	19,619	$ 79,508
Short-term investments	18,333		$ 23,603
Equity method investments, additional investment	4,000
Equity method investment, carrying value	6,700
Operating lease right-of-use assets	78,263
Lease liabilities	$ 85,579
ASU 2016-02
Summary Of Significant Accounting Policies [Line Items]
Operating lease right-of-use assets				$ 80,000
Lease liabilities				$ 80,000
Payment Technology and Services Company
Summary Of Significant Accounting Policies [Line Items]
Equity method investment, noncontrolling interest	8.00%
Maximum
Summary Of Significant Accounting Policies [Line Items]
Short-term investment contractual maturities	2 years		2 years
Cloud and Related Solutions Revenue | Minimum
Summary Of Significant Accounting Policies [Line Items]
Future revenue including variable consideration, contractual terms ending, year	2019
Cloud and Related Solutions Revenue | Maximum
Summary Of Significant Accounting Policies [Line Items]
Future revenue including variable consideration, contractual terms ending, year	2028