Debt - Additional Information (Detail) - USD ($)					12 Months Ended
		Nov. 10, 2016	Oct. 27, 2016	Apr. 19, 2016	Dec. 31, 2016		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013	Mar. 31, 2019	Sep. 30, 2016	Sep. 30, 2015	Jun. 18, 2013
Debt Instrument [Line Items]
Debt instrument principal amount					$ 1,386,813,000		$ 692,058,000
Debt instrument capitalized amount							3,300,000
Payments for 1.25% Call Option									$ 82,800,000
Proceeds from issuance of warrants, net of issuance costs									51,200,000
Net cash payment for 1.25% Notes call spread overlay									31,600,000
Maximum percentage of foreign subsidiary capital stock guaranteeing credit facility					65.00%
Deferred debt issuance cost written off with existing Credit Facility					$ 5,224,000		1,433,000	$ 0
HealthMEDX, LLC [Member]
Debt Instrument [Line Items]
Proceeds from debt			$ 36,195,000
Consideration paid for acquisitions			2,888,000
Letter of Credit [Member]
Debt Instrument [Line Items]
Portion of facility available for issuance of letters of credit												$ 50,000,000
Line of Credit [Member]
Debt Instrument [Line Items]
Portion of facility available for issuance of swingline loans												10,000,000
Netsmart Revolving Facility [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, effective percentage					5.75%
Netsmart Revolving Facility [Member] | LIBOR Rate [Member]
Debt Instrument [Line Items]
Senior secured credit facility interest rate spread					4.75%
1.25% Cash Convertible Senior Notes [Member]
Debt Instrument [Line Items]
Debt instrument principal amount					$ 345,000,000	[1]	345,000,000						$ 345,000,000
Proceeds from debt					$ 305,100,000
Interest payment, terms					Interest on the 1.25% Notes is payable semiannually in arrears on January 1 and July 1 of each year
Debt, Maturity date					Jul. 01, 2020
Debt instrument convertible, principal amount					$ 1,000
Convertible number of equity instrument					58.1869
Conversion price per common stock					$ 17.19
Repurchase percentage on principal					100.00%
Fair value liability of embedded cash conversion option					$ 82,800,000
Convertible debt instrument remaining discount amortization period					3 years 6 months
Debt instrument, interest rate, effective percentage					5.40%
Interest rate					1.25%
Debt Instrument, fees and aggregate cost					$ 8,400,000
Debt instrument capitalized amount					8,300,000
Deferred charges capitalized amount outstanding					4,100,000
Accrued and unpaid interest					$ 2,200,000
Payments for 1.25% Call Option									$ 82,800,000
1.25% Cash Convertible Senior Notes [Member] | Condition One [Member]
Debt Instrument [Line Items]
Threshold trading days					20 days
Threshold consecutive trading days					30 days
Debt instrument conversion price percentage					130.00%
1.25% Cash Convertible Senior Notes [Member] | Condition Two [Member]
Debt Instrument [Line Items]
Threshold trading days					5 days
Threshold consecutive trading days					5 days
Debt instrument conversion price percentage					98.00%
Debt instrument convertible, principal amount					$ 1,000
Senior Secured Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument principal amount	[2]				$ 234,375,000
Credit facility, maximum borrowing capacity												250,000,000
Term Loan repayment, end date					Sep. 30, 2020
Credit facility, increase in total borrowing limits												25,000,000
Senior secured credit facilities term, years					5 years
Senior Secured Revolving Facility [Member]
Debt Instrument [Line Items]
Debt instrument principal amount					$ 207,500,000
Credit facility, maximum borrowing capacity												550,000,000
Credit facility, increase in total borrowing limits												125,000,000
Credit facility, maximum borrowing capacity, foreign currencies												$ 100,000,000
Senior secured credit facilities term, years					5 years
Applicable margin for borrowings based on federal funds rate					0.50%
Initial margin for borrowings based on non-Eurocurrency rate					1.25%
Initial margin for borrowings based on Eurocurrency rate					2.25%
Basis point reduction in applicable interest rate margin ranges					0.50%
Credit facility borrowing capacity, amount available					$ 341,700,000
Senior Secured Revolving Facility [Member] | Eurocurrency Rate for U.S. Dollars [Member]
Debt Instrument [Line Items]
Senior secured credit facility interest rate spread					1.00%
Senior Secured Revolving Facility [Member] | 2015 Credit Agreement [Member] | Base Rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Senior secured credit facility interest rate spread					0.00%
Senior Secured Revolving Facility [Member] | 2015 Credit Agreement [Member] | Base Rate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Senior secured credit facility interest rate spread					1.25%
Senior Secured Revolving Facility [Member] | 2015 Credit Agreement [Member] | Eurocurrency Rate [Member] | Minimum [Member]
Debt Instrument [Line Items]
Senior secured credit facility interest rate spread					1.00%
Senior Secured Revolving Facility [Member] | 2015 Credit Agreement [Member] | Eurocurrency Rate [Member] | Maximum [Member]
Debt Instrument [Line Items]
Senior secured credit facility interest rate spread					2.25%
Senior Secured Credit Facility [Member]
Debt Instrument [Line Items]
Debt instrument principal amount					$ 441,875,000		346,875,000
Aggregate amount of additional credit facilities authorized					300,000,000
Letters of credit outstanding					$ 800,000
Senior Secured Credit Facility [Member] | United States dollars [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, effective percentage					2.77%
Senior Secured Credit Facility [Member] | Minimum [Member]
Debt Instrument [Line Items]
Interest coverage ratio					400.00%
Senior Secured Credit Facility [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio					400.00%
Secured leverage ratio					300.00%
Senior Secured Credit Facility [Member] | LIBOR Rate [Member]
Debt Instrument [Line Items]
Senior secured credit facility interest rate spread					2.00%
Senior Secured Credit Facility [Member] | 2015 Credit Agreement [Member]
Debt Instrument [Line Items]
Debt Instrument, fees and aggregate cost							3,000,000
Debt issuance costs capitalized							2,700,000
Deferred debt issuance cost written off with existing Credit Facility							1,100,000
Debt Instrument fees and other costs expensed							$ 300,000
Senior Secured Credit Facility [Member] | 2015 Credit Agreement [Member] | Minimum [Member] | Covenant On Potential Acquisition [Member]
Debt Instrument [Line Items]
Consideration paid for acquisitions					$ 100,000,000
Senior Secured Credit Facility [Member] | 2015 Credit Agreement [Member] | Maximum [Member] | Covenant On Potential Acquisition [Member]
Debt Instrument [Line Items]
Leverage ratio					450.00%
Secured leverage ratio					325.00%
Netsmart First Lien Credit Agreement [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, effective percentage					5.50%
Debt instrument capitalized amount		$ 0
Deferred debt issuance cost written off with existing Credit Facility		$ 5,224,000
Decrease in effective interest rate		(0.25%)
Netsmart First Lien Credit Agreement [Member] | Netsmart First Lien Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument principal amount					$ 432,900,000
Credit facility, maximum borrowing capacity				$ 395,000,000
Senior secured credit facilities term, years				7 years
Credit facility termination date				Apr. 19, 2023
Netsmart First Lien Credit Agreement [Member] | Minimum [Member] | Scenario Forecast [Member]
Debt Instrument [Line Items]
Leverage ratio										6.75%
Netsmart First Lien Credit Agreement [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio											8.75%
Netsmart First Lien Credit Agreement [Member] | LIBOR Rate [Member]
Debt Instrument [Line Items]
Senior secured credit facility interest rate spread				4.25%	4.50%
Netsmart First Lien Credit Agreement [Member] | LIBOR Rate [Member] | Netsmart First Lien Term Loan [Member]
Debt Instrument [Line Items]
Senior secured credit facility interest rate spread				4.50%
Netsmart First Lien Credit Agreement [Member] | Alternate Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, effective percentage				3.25%
Netsmart First Lien Credit Agreement [Member] | Alternate Base Rate Loans [Member] | Netsmart First Lien Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, effective percentage				3.50%
Netsmart First Lien Credit Agreement [Member] | Netsmart Revolving Facility [Member]
Debt Instrument [Line Items]
Debt instrument principal amount					$ 1,500,000
Credit facility, maximum borrowing capacity				$ 50,000,000
Senior secured credit facilities term, years				5 years
Credit facility borrowing capacity, amount available					$ 48,500,000
Credit facility termination date				Apr. 19, 2021
Netsmart First Lien Credit Agreement [Member] | Netsmart Revolving Facility [Member] | LIBOR Rate [Member]
Debt Instrument [Line Items]
Senior secured credit facility interest rate spread				4.75%
Netsmart First Lien Credit Agreement [Member] | Netsmart Revolving Facility [Member] | Alternate Base Rate Loans [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, effective percentage				3.75%
Netsmart Second Lien Credit Agreement [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, effective percentage					10.50%
Netsmart Second Lien Credit Agreement [Member] | Netsmart Second Lien Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument principal amount					$ 167,000,000
Credit facility, maximum borrowing capacity				$ 167,000,000
Senior secured credit facilities term, years				7 years 6 months
Credit facility termination date				Oct. 19, 2023
Netsmart Second Lien Credit Agreement [Member] | Minimum [Member] | Scenario Forecast [Member]
Debt Instrument [Line Items]
Leverage ratio										7.75%
Netsmart Second Lien Credit Agreement [Member] | Maximum [Member]
Debt Instrument [Line Items]
Leverage ratio											9.75%
Netsmart Second Lien Credit Agreement [Member] | LIBOR Rate [Member]
Debt Instrument [Line Items]
Senior secured credit facility interest rate spread					9.50%
Netsmart Second Lien Credit Agreement [Member] | LIBOR Rate [Member] | Netsmart Second Lien Term Loan [Member]
Debt Instrument [Line Items]
Senior secured credit facility interest rate spread				9.50%
Netsmart Second Lien Credit Agreement [Member] | Alternate Base Rate Loans [Member] | Netsmart Second Lien Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument, interest rate, effective percentage				8.50%
Netsmart First Lien Term Loan [Member]
Debt Instrument [Line Items]
Debt instrument principal amount	[2]				$ 432,925,000
Netsmart First Lien Term Loan [Member] | HealthMEDX, LLC [Member]
Debt Instrument [Line Items]
Debt instrument capitalized amount			600,000
Credit facility, maximum borrowing capacity			$ 40,000,000
Netsmart Credit Agreements [Member]
Debt Instrument [Line Items]
Debt issuance costs capitalized					$ 27,900,000

[1] Assumes no cash conversions of the 1.25% Notes prior to their maturity on July 1, 2020.

[2] Assumes no additional borrowings after December 31, 2016 and that all drawn amounts are repaid upon maturity.