Business Combinations - Summary of Purchase Price Allocation (Details) - USD ($) $ in Thousands	Dec. 31, 2017	Aug. 16, 2017	Apr. 14, 2017	Mar. 31, 2017
Preliminary fair value of identifiable intangible assets acquired:
Goodwill	$ 216,530			$ 185,898
Entrada [Member]
Preliminary fair value of the net tangible assets acquired and liabilities assumed:
Acquired cash and cash equivalents			$ 102
Accounts receivable, net			1,835
Prepaid expense and other current assets			145
Equipment and improvements, net			134
Capitalized software costs, net			364
Deferred income taxes, net			1,041
Accounts payable			(639)
Accrued compensation and related benefits			(120)
Deferred revenues			(234)
Other liabilities			(444)
Total preliminary net tangible assets acquired and liabilities assumed			2,184
Preliminary fair value of identifiable intangible assets acquired:
Goodwill			16,374
Total preliminary identifiable intangible assets acquired			31,774
Total preliminary purchase price			33,958
Entrada [Member] | Computer Software, Intangible Asset
Preliminary fair value of identifiable intangible assets acquired:
Total preliminary identifiable intangible assets acquired			10,500
Entrada [Member] | Customer Relationships
Preliminary fair value of identifiable intangible assets acquired:
Total preliminary identifiable intangible assets acquired			3,300
Entrada [Member] | Trade Names
Preliminary fair value of identifiable intangible assets acquired:
Total preliminary identifiable intangible assets acquired			$ 1,600
EagleDream Health [Member]
Preliminary fair value of the net tangible assets acquired and liabilities assumed:
Acquired cash and cash equivalents		$ 573
Accounts receivable, net		217
Prepaid expense and other current assets		20
Accounts payable		(115)
Accrued compensation and related benefits		(271)
Deferred revenues		(394)
Other liabilities		(122)
Total preliminary net tangible assets acquired and liabilities assumed		(2,049)
Deferred income taxes, net		(1,957)
Preliminary fair value of identifiable intangible assets acquired:
Goodwill		14,258
Total preliminary identifiable intangible assets acquired		27,658
Total preliminary purchase price		25,609
EagleDream Health [Member] | Computer Software, Intangible Asset
Preliminary fair value of identifiable intangible assets acquired:
Total preliminary identifiable intangible assets acquired		12,800
EagleDream Health [Member] | Customer Relationships
Preliminary fair value of identifiable intangible assets acquired:
Total preliminary identifiable intangible assets acquired		$ 600