Segment Information - Segment Information (Detail) - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017	Dec. 31, 2017
Segment Reporting Information [Line Items]
Revenue By Payor	100.00%	100.00%	100.00%	100.00%
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Net service revenue	$ 502,024	$ 257,535	$ 793,078	$ 501,784
Cost of service revenue	329,646	161,158	518,264	315,528
General and administrative expenses	141,350	73,552	233,381	145,563
Operating income	31,028	22,825	41,433	40,693
Interest expense	(3,202)	(840)	(4,652)	(1,620)
Income before income taxes and noncontrolling interest	27,826	21,985	36,781	39,073
Income tax expense	7,170	7,792	8,147	12,965
Net income	20,656	14,193	28,634	26,108
Less net income (loss) attributable to noncontrolling interests	3,859	2,889	6,842	5,337
Net income attributable to LHC Group, Inc.’s common stockholders	16,797	11,304	21,792	20,771
Total assets	1,881,670	672,666	$ 1,881,670	672,666	$ 793,702
Document Fiscal Year Focus			2018
Home health services
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Net service revenue	360,276	192,409	$ 564,463	373,067
Cost of service revenue	230,293	117,606	360,453	229,692
General and administrative expenses	99,162	55,268	165,452	109,190
Operating income	30,821	19,535	38,558	34,185
Interest expense	(2,256)	(630)	(3,343)	(1,215)
Income before income taxes and noncontrolling interest	28,565	18,905	35,215	32,970
Income tax expense	7,091	6,757	7,813	11,010
Net income	21,474	12,148	27,402	21,960
Less net income (loss) attributable to noncontrolling interests	3,810	2,266	6,047	4,294
Net income attributable to LHC Group, Inc.’s common stockholders	17,664	9,882	21,355	17,666
Total assets	1,306,773	466,308	1,306,773	466,308
Hospice services
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Net service revenue	50,554	37,851	93,180	73,799
Cost of service revenue	33,493	24,473	61,512	47,746
General and administrative expenses	14,613	10,743	27,910	21,149
Operating income	2,448	2,635	3,758	4,904
Interest expense	(473)	(126)	(690)	(243)
Income before income taxes and noncontrolling interest	1,975	2,509	3,068	4,661
Income tax expense	483	849	594	1,508
Net income	1,492	1,660	2,474	3,153
Less net income (loss) attributable to noncontrolling interests	412	480	829	766
Net income attributable to LHC Group, Inc.’s common stockholders	1,080	1,180	1,645	2,387
Total assets	189,447	138,519	189,447	138,519
Home and community-based services
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Net service revenue	52,753	10,746	66,844	21,287
Cost of service revenue	40,349	7,986	51,139	15,934
General and administrative expenses	11,777	2,261	15,075	4,572
Operating income	627	499	630	781
Interest expense	(158)	(42)	(230)	(81)
Income before income taxes and noncontrolling interest	469	457	400	700
Income tax expense	139	180	124	263
Net income	330	277	276	437
Less net income (loss) attributable to noncontrolling interests	(90)	5	(70)	13
Net income attributable to LHC Group, Inc.’s common stockholders	420	272	346	424
Total assets	255,456	33,292	255,456	33,292
Facility-based services
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Net service revenue	28,304	16,529	58,454	33,631
Cost of service revenue	19,307	11,093	38,956	22,156
General and administrative expenses	11,088	5,280	20,234	10,652
Operating income	(2,091)	156	(736)	823
Interest expense	(159)	(42)	(232)	(81)
Income before income taxes and noncontrolling interest	(2,250)	114	(968)	742
Income tax expense	(313)	6	(154)	184
Net income	(1,937)	108	(814)	558
Less net income (loss) attributable to noncontrolling interests	(207)	138	102	264
Net income attributable to LHC Group, Inc.’s common stockholders	(1,730)	(30)	(916)	294
Total assets	66,665	$ 34,547	66,665	$ 34,547
HCI
Segment Reporting Information [Line Items]
Revenue By Payor		0.00%		0.00%
Segment Reporting, Disclosure of Entity's Reportable Segments [Abstract]
Net service revenue	10,137	$ 0	10,137	$ 0
Cost of service revenue	6,204	0	6,204	0
General and administrative expenses	4,710	0	4,710	0
Operating income	(777)	0	(777)	0
Interest expense	(156)	0	(157)	0
Income before income taxes and noncontrolling interest	(933)	0	(934)	0
Income tax expense	(230)	0	(230)	0
Net income	(703)	0	(704)	0
Less net income (loss) attributable to noncontrolling interests	(66)	0	(66)	0
Net income attributable to LHC Group, Inc.’s common stockholders	(637)	0	(638)
Total assets	$ 63,329	$ 0	$ 63,329	$ 0
Home Health Medicare
Segment Reporting Information [Line Items]
Revenue By Payor	72.90%	72.40%	72.30%	73.00%
Hospice Medicare
Segment Reporting Information [Line Items]
Revenue By Payor	91.10%	92.90%	91.70%	93.50%
Community Based Services Medicaid
Segment Reporting Information [Line Items]
Revenue By Payor	24.70%	18.00%	23.10%	17.30%
Facility-Based Medicare revenue
Segment Reporting Information [Line Items]
Revenue By Payor	58.70%	65.00%	61.40%	64.40%