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Percentage points added to the reference rate to compute the variable rate on the debt instrument.

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Face (par) amount of debt instrument at time of issuance.

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Amount, before accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Amount, after accumulated amortization, of debt issuance costs. Includes, but is not limited to, legal, accounting, underwriting, printing, and registration costs.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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The percentage of loan attributable to amortization per year.

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Minimum reference rate for the variable rate of the debt instrument.

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Debt (Details) - USD ($)		3 Months Ended		12 Months Ended
Debt (Details) - USD ($)	Jul. 31, 2015	Mar. 31, 2019	Mar. 31, 2018	Dec. 31, 2016	Jan. 31, 2019
Credit facility
Long term debt, gross		$ 412,110,000
Amortization of deferred financing costs		630,000	$ 601,000
Excess cash flows, repayment of debt, percentage				50.00%
Excess cash flows threshold for dividends				$ 5,000,000.0
Term loan
Credit facility
Fair value of debt		401,000,000.0
Debt issuance costs incurred	$ 12,900,000	12,900,000
Deferred issuance costs, net		5,600,000
Face amount	$ 425,000,000.0
Amortization per year (as a percent)	1.00%
Long term debt, gross		410,100,000
Amortization of deferred financing costs		600,000	$ 600,000
Revolving loan
Credit facility
Debt issuance costs incurred	$ 1,300,000
Maximum borrowing available	$ 25,000,000.0				$ 12,500,000
Long term debt, gross		0
Letter-of-credit sub-facility
Credit facility
Maximum borrowing available					$ 10,000,000.0
Credit Facility \| Alternate base rate
Credit facility
Margin of interest (as a percent)	3.75%
Credit Facility \| LIBOR
Credit facility
Margin of interest (as a percent)	4.75%
Variable rate base minimum (as a percent)	1.00%
Prepayment due to Excess Cash Flow provision \| Term loan
Credit facility
Repayments of principal in next 12 months		$ 0