Revenue from Contracts with Customers - Schedule of Revenues Disaggregated by Major Revenue Categories and by Occurrence (Details) - USD ($) $ in Thousands	3 Months Ended								12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Disaggregation Of Revenue [Line Items]
Total revenues	$ 134,785	$ 130,867	$ 130,321	$ 133,200	$ 135,775	$ 131,715	$ 132,607	$ 130,922	$ 529,173	$ 531,019	$ 509,624
Subscription Services
Disaggregation Of Revenue [Line Items]
Total revenues									117,502	106,325	94,118
Support And Maintenance
Disaggregation Of Revenue [Line Items]
Total revenues									160,798	163,805	158,802
Managed Services
Disaggregation Of Revenue [Line Items]
Total revenues									98,203	113,311	106,454
Electronic Data Interchange And Data Services
Disaggregation Of Revenue [Line Items]
Total revenues									97,418	92,773	88,951
Recurring
Disaggregation Of Revenue [Line Items]
Total revenues	120,151	117,446	116,317	120,007	118,598	118,997	119,441	119,178	473,921	476,214	448,325
Software License and Hardware
Disaggregation Of Revenue [Line Items]
Total revenues									35,122	34,017	44,145
Other Non-recurring Services
Disaggregation Of Revenue [Line Items]
Total revenues									20,130	20,788	17,154
Software, Hardware, and Other Non-recurring
Disaggregation Of Revenue [Line Items]
Total revenues	$ 14,634	$ 13,421	$ 14,004	$ 13,193	$ 17,177	$ 12,718	$ 13,166	$ 11,744	$ 55,252	$ 54,805	$ 61,299