Segment Information - Summary of segment Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017	Dec. 31, 2017
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Net service revenue	$ 507,043	$ 269,678	$ 1,300,121	$ 771,462
Cost of service revenue	322,196	172,856	831,818	488,384
General and administrative expenses	149,917	75,492	391,940	221,054
Operating income	34,930	21,330	76,363	62,024
Interest expense	(3,264)	(995)	(7,916)	(2,615)
Income before income taxes and noncontrolling interest	31,666	20,335	68,447	59,409
Income tax expense	6,685	7,445	14,832	20,410
Net income	24,981	12,890	53,615	38,999
Less net income (loss) attributable to noncontrolling interests	3,751	1,984	10,593	7,321
Net income attributable to LHC Group, Inc.’s common stockholders	21,230	10,906	43,022	31,678
Total assets	1,910,764	765,053	1,910,764	765,053	$ 793,702
Home health services
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Net service revenue	360,000	196,317	924,463	569,384
Cost of service revenue	222,765	123,204	576,416	352,896
General and administrative expenses	105,457	56,000	277,711	165,192
Operating income	31,778	17,113	70,336	51,296
Interest expense	(2,284)	(746)	(5,627)	(1,961)
Income before income taxes and noncontrolling interest	29,494	16,367	64,709	49,335
Income tax expense	6,209	5,703	14,022	16,712
Net income	23,285	10,664	50,687	32,623
Less net income (loss) attributable to noncontrolling interests	3,425	1,759	9,472	6,053
Net income attributable to LHC Group, Inc.’s common stockholders	19,860	8,905	41,215	26,570
Total assets	1,316,792	515,562	1,316,792	515,562
Hospice services
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Net service revenue	52,962	41,057	146,142	114,856
Cost of service revenue	34,540	27,441	95,557	75,187
General and administrative expenses	14,685	11,276	43,090	32,425
Operating income	3,737	2,340	7,495	7,244
Interest expense	(491)	(149)	(1,181)	(393)
Income before income taxes and noncontrolling interest	3,246	2,191	6,314	6,851
Income tax expense	774	931	1,368	2,439
Net income	2,472	1,260	4,946	4,412
Less net income (loss) attributable to noncontrolling interests	386	273	1,215	1,038
Net income attributable to LHC Group, Inc.’s common stockholders	2,086	987	3,731	3,374
Total assets	203,921	156,296	203,921	156,296
Home and community-based services
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Net service revenue	52,773	12,116	119,617	33,403
Cost of service revenue	39,860	8,971	90,331	24,905
General and administrative expenses	12,922	2,387	28,664	6,957
Operating income	(9)	758	622	1,541
Interest expense	(163)	(50)	(393)	(130)
Income before income taxes and noncontrolling interest	(172)	708	229	1,411
Income tax expense	(74)	338	50	602
Net income	(98)	370	179	809
Less net income (loss) attributable to noncontrolling interests	(87)	(21)	(157)	(7)
Net income attributable to LHC Group, Inc.’s common stockholders	(11)	391	336	816
Total assets	246,963	44,621	246,963	44,621
Facility-based services
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Net service revenue	27,891	20,188	86,345	53,819
Cost of service revenue	20,146	13,240	59,102	35,396
General and administrative expenses	9,823	5,829	30,058	16,480
Operating income	(2,078)	1,119	(2,815)	1,943
Interest expense	(163)	(50)	(395)	(131)
Income before income taxes and noncontrolling interest	(2,241)	1,069	(3,210)	1,812
Income tax expense	(541)	473	(695)	657
Net income	(1,700)	596	(2,515)	1,155
Less net income (loss) attributable to noncontrolling interests	27	(27)	129	237
Net income attributable to LHC Group, Inc.’s common stockholders	(1,727)	623	(2,644)	918
Total assets	61,089	48,574	61,089	48,574
HCI
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Net service revenue	13,417	0	23,554	0
Cost of service revenue	4,885	0	10,412	0
General and administrative expenses	7,030	0	12,417	0
Operating income	1,502	0	725	0
Interest expense	(163)	0	(320)	0
Income before income taxes and noncontrolling interest	1,339	0	405	0
Income tax expense	317	0	87	0
Net income	1,022	0	318	0
Less net income (loss) attributable to noncontrolling interests	0	0	(66)	0
Net income attributable to LHC Group, Inc.’s common stockholders	1,022	0	384	0
Total assets	$ 81,999	$ 0	$ 81,999	$ 0