Financing Arrangements - Schedule of Term Facility Financial Covenant (Detail)	12 Months Ended	15 Months Ended	39 Months Ended
Mar. 31, 2019	Mar. 31, 2018	Jun. 30, 2022
2017 Facility [Member] \| Scenario, Forecast [Member]
Debt Instrument [Line Items]
Total Net Leverage Ratio	4.75%	5.00%	4.50%

Represents the net leverage ratio for the covenants. Contains a number of affirmative, negative, reporting and financial covenants, in each case subject to certain exceptions and materiality thresholds. Required to be in quarterly compliance, measured on a trailing four quarter basis. contains usual and customary restrictions on the ability of the Company and its subsidiaries to: (i) incur additional indebtedness (ii) create liens; (iii) consolidate, merge, sell or otherwise dispose of all or substantially all of its assets; (iv) sell certain assets; (v) pay dividends on, repurchase or make distributions in respect of capital stock or make other restricted payments; (vi) make certain investments; (vii) repay subordinated indebtedness prior to stated maturity; and (viii) enter into certain transactions with its affiliates.

No definition available.

Name:	lnth_DebtInstrumentCovenantLeverageRatio
Namespace Prefix:	lnth_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration