Summary of Long-term Equity Investments Included in Other Assets (Detail) $ in Thousands		3 Months Ended
		Mar. 31, 2019 USD ($) Investment	Dec. 31, 2018 USD ($)
Fair Value Disclosures [Abstract]
Equity method investments, Number of Investees | Investment	[1]	5
Cost method investments, Number of Investees | Investment		8
Total long-term equity investments, Number of Investees | Investment		13
Equity method investments, Original Cost	[1]	$ 7,407
Cost method investments, Original Cost		37,874
Total long-term equity investments, Original Cost		45,281
Equity method investments, Carrying Value		10,604	$ 10,667
Cost method investments, Carrying Value		26,935	25,923
Total long-term equity investments, Carrying Value		$ 37,539	$ 36,590

[1] Allscripts share of the earnings of our equity method investees is reported based on a one quarter lag.