Basis of Presentation, Summary of Significant Accounting Policies and Changes in Accounting Principles - Change in Accounting Principle (Details) - USD ($) $ in Thousands		3 Months Ended		9 Months Ended
		Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Jan. 01, 2018	Dec. 31, 2017
Revenue
Revenues		$ 149,947	$ 107,912	$ 433,959	$ 321,221
Expenses
Cost of revenue (exclusive of depreciation and amortization expenses)	[1]	73,967	68,281	214,945	203,804
Selling, general and administrative expenses	[1]	59,566	45,834	172,495	150,474
Income (loss) before income taxes and non-controlling interests		(12,420)	(14,843)	(36,622)	(57,986)
ASSETS
Accounts receivable, net		60,054		60,054			$ 48,947
Contract assets (current)		3,705		3,705		$ 3,710	0
Contract assets (noncurrent)		1,000		1,000		1,791	0
Contract cost assets		14,252		14,252			0
Liabilities
Deferred revenue		22,360		22,360		$ 26,147	24,807
Other long-term liabilities		10,885		10,885			9,861
Shareholders' Equity (Deficit)
Retained earnings (accumulated deficit)		66,696		66,696			85,952
Non-controlling interests		10,008		10,008			$ 35,427
Balances without adoption of ASC 606
Expenses
Cost of revenue (exclusive of depreciation and amortization expenses)		77,409		218,786
Selling, general and administrative expenses		59,676		173,644
Income (loss) before income taxes and non-controlling interests		(15,798)		(42,063)
ASSETS
Accounts receivable, net		57,848		57,848
Contract assets (current)		0		0
Contract assets (noncurrent)		0		0
Contract cost assets		0		0
Liabilities
Deferred revenue		24,100		24,100
Other long-term liabilities		10,746		10,746
Shareholders' Equity (Deficit)
Retained earnings (accumulated deficit)		44,580		44,580
Non-controlling interests		9,361		9,361
Impact of adoption Higher/(Lower)
Revenue
Revenues		(214)	(449)	(647)	(1,224)
Impact of adoption Higher/(Lower) | Accounting Standards Update 2014-09
Revenue
Revenues				(4,498)
Expenses
Cost of revenue (exclusive of depreciation and amortization expenses)		(3,442)		(3,841)
Selling, general and administrative expenses		(110)		(1,149)
Income (loss) before income taxes and non-controlling interests		3,378		5,441
ASSETS
Accounts receivable, net		2,206		2,206
Contract assets (current)		3,705		3,705
Contract assets (noncurrent)		1,000		1,000
Contract cost assets		14,252		14,252
Liabilities
Deferred revenue		(1,740)		(1,740)
Other long-term liabilities		139		139
Shareholders' Equity (Deficit)
Retained earnings (accumulated deficit)		22,116		22,116
Non-controlling interests		647		647
Transformation services
Revenue
Revenues	[1]	9,230	8,204	23,950	23,799
Transformation services | Balances without adoption of ASC 606
Revenue
Revenues		9,556		25,272
Transformation services | Impact of adoption Higher/(Lower) | Accounting Standards Update 2014-09
Revenue
Revenues		(326)		(1,322)
Platform and operations services
Revenue
Revenues	[1]	118,094	$ 99,708	341,258	$ 297,422
Platform and operations services | Balances without adoption of ASC 606
Revenue
Revenues		117,942		339,485
Platform and operations services | Impact of adoption Higher/(Lower) | Accounting Standards Update 2014-09
Revenue
Revenues		$ 152		$ 1,773

[1] See Note 16 for amounts related to affiliates included in these line items.