Debt and Financial Instruments - Additional Information (Detail) | Mar. 27, 2018USD ($)Option | Mar. 31, 2020USD ($)Derivative | Jan. 31, 2020USD ($)Derivative | Jun. 30, 2020USD ($) | Sep. 30, 2019USD ($)Derivative | Mar. 31, 2019USD ($) | Sep. 30, 2016USD ($)Derivative | Jun. 30, 2016USD ($)Derivative | Jun. 30, 2020USD ($) | Dec. 31, 2018USD ($) | Mar. 31, 2019USD ($) | Mar. 31, 2019USD ($) | Dec. 31, 2019USD ($) |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Outstanding borrowings under revolving credit agreement | | | | $ 221,250,000 | | | | | $ 221,250,000 | | | | $ 212,950,000 |
Letters of credit outstanding | | | | 5,600 | | | | | 5,600 | | | | |
Available borrowing capacity | | | | 123,100,000 | | | | | 123,100,000 | | | | 87,000,000 |
Compensating balance | | | | 0 | | | | | 0 | | | | |
Interest Rate Swap | Cash Flow Hedge | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Number of interest rate cap agreements | Derivative | | 1 | 1 | | 1 | | | | | | | | |
Derivative instruments, fixed rate | | 0.565% | 1.4975% | | 1.144% | | | | | | | | |
Notional amount | | $ 55,000,000 | $ 35,000,000 | | $ 50,000,000 | | | | | | | | |
Expiration date of interest rate | | Mar. 25, 2027 | Sep. 16, 2024 | | Sep. 16, 2024 | | | | | | | | |
Interest Rate Cap | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Number of interest rate cap agreements | Derivative | | | | | | | 1 | 1 | | | | | |
Notional amount | | | | | | | $ 30,000,000 | $ 30,000,000 | | | | | |
Expiration date of interest rate | | | | | | | Mar. 31, 2019 | Mar. 31, 2019 | | | | | |
Derivative interest rate cap, payment received or accrued from counterparties | | | | | | $ 61,000 | | | | $ 144,000 | $ 205,000 | $ 205,000 | |
Premium paid | | | | | | | $ 55,000 | $ 115,000 | | | | | |
Level 2 | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Mortgage loan fair value | | | | 62,400,000 | | | | | 62,400,000 | | | | 63,100,000 |
Mortgage debt | | | | | | | | | | | | | $ 61,100,000 |
Derivative interest rate cap, net payment received or accrued from counterparties | | | | | | | | | 23,000 | | | | |
Derivative interest rate cap, payment received or accrued from counterparties | | | | | | | | | 199,000 | | | | |
Derivative interest rate cap, offset due to counterparties | | | | | | | | | 222,000 | | | | |
Level 2 | Interest Rate Swap | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Liability derivatives, fair value | | | | 4,900,000 | | | | | 4,900,000 | | | | |
Derivative interest rate cap, net payment received or accrued from counterparties | | | | 182,000 | | | | | 131,000 | | | | |
Derivative interest rate cap, payment received or accrued from counterparties | | | | 201,000 | | | | | 222,000 | | | | |
Derivative interest rate cap, offset due to counterparties | | | | 19,000 | | | | | 91,000 | | | | |
LIBOR | Interest Rate Cap | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Derivative instruments, LIBOR rate | | | | | | | 1.50% | 1.50% | | | | | |
Credit Agreement | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Outstanding borrowing | | | | 350,000,000 | | | | | 350,000,000 | | | | |
Credit Agreement | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Outstanding borrowing | $ 350,000,000 | | | | | | | | | | | | |
Unsecured revolving amended credit agreement terminated date | 2022-03 | | | | | | | | | | | | |
Number of additional six month extension options | Option | 2 | | | | | | | | | | | | |
Credit Agreement | Swingline/Short-Term Loans | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Outstanding borrowing | $ 30,000,000 | | | | | | | | | | | | |
Credit Agreement | Letters of Credit | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Outstanding borrowing | $ 40,000,000 | | | | | | | | | | | | |
Revolving B Facility | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Outstanding borrowing | | | | $ 300,000,000 | | | | | 300,000,000 | | | | |
Proceeds from lines of credit | | | | | | | | | 50,000,000 | | | | |
Increase in borrowing capacity | | | | | | | | | $ 350,000,000 | | | | |
Credit facility, Interest Rate Terms | | | | | | | | | one, two, three, or six months LIBOR plus an applicable margin ranging from 1.85% to 2.10% or at the Base Rate plus an applicable margin ranging from 0.85% to 1.10%. | | | | |
Base rate description | | | | | | | | | the greatest of (a) the Administrative Agent’s prime rate, (b) the federal funds effective rate plus 1/2 of 1% and (c) one month LIBOR plus 1%. | | | | |
Facility fee payable on commitment | | | | | | | | | 0.20% | | | | |
Revolving B Facility | LIBOR | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Margin points added to the reference rate | 1.95% | | | | | | | | 1.95% | | | | |
Revolving B Facility | Base Rate | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Margin points added to the reference rate | 0.95% | | | | | | | | 0.95% | | | | |
Revolving B Facility | Minimum | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Facility fee payable on commitment | 0.15% | | | | | | | | | | | | |
Revolving B Facility | Minimum | LIBOR | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Margin points added to the reference rate | 1.85% | | | | | | | | | | | | |
Margin points added to the base rate | 1.00% | | | | | | | | | | | | |
Revolving B Facility | Minimum | Base Rate | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Margin points added to the reference rate | 0.85% | | | | | | | | | | | | |
Revolving B Facility | Minimum | Federal Funds Effective Rate | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Margin points added to the base rate | 0.50% | | | | | | | | | | | | |
Revolving B Facility | Maximum | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Facility fee payable on commitment | 0.35% | | | | | | | | | | | | |
Revolving B Facility | Maximum | LIBOR | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Margin points added to the reference rate | 2.10% | | | | | | | | | | | | |
Revolving B Facility | Maximum | Base Rate | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Margin points added to the reference rate | 1.10% | | | | | | | | | | | | |
Revolving A Facility | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Credit facility, Interest Rate Terms | | | | | | | | | one, two, three, or six-month LIBOR plus an applicable margin ranging from 1.10% to 1.35% or at the Base Rate plus an applicable margin ranging from 0.10% to 0.35%. | | | | |
Base rate description | | | | | | | | | the greater of: (a) the administrative agent’s prime rate; (b) the federal funds effective rate plus 1/2 of 1%, and; (c) one month LIBOR plus 1%. | | | | |
Facility fee payable on commitment | | | | | | | | | 0.20% | | | | |
Revolving A Facility | LIBOR | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Margin points added to the reference rate | | | | | | | | | 1.20% | | | | |
Revolving A Facility | Base Rate | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Margin points added to the reference rate | | | | | | | | | 0.20% | | | | |
Revolving A Facility | Minimum | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Facility fee payable on commitment | 0.15% | | | | | | | | | | | | |
Revolving A Facility | Minimum | LIBOR | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Margin points added to the reference rate | 1.10% | | | | | | | | | | | | |
Margin points added to the base rate | 1.00% | | | | | | | | | | | | |
Revolving A Facility | Minimum | Base Rate | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Margin points added to the reference rate | 0.10% | | | | | | | | | | | | |
Revolving A Facility | Minimum | Federal Funds Effective Rate | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Margin points added to the base rate | 0.50% | | | | | | | | | | | | |
Revolving A Facility | Maximum | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Facility fee payable on commitment | 0.35% | | | | | | | | | | | | |
Revolving A Facility | Maximum | LIBOR | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Margin points added to the reference rate | 1.35% | | | | | | | | | | | | |
Revolving A Facility | Maximum | Base Rate | | | | | | | | | | | | | |
Debt Instrument [Line Items] | | | | | | | | | | | | | |
Margin points added to the reference rate | 0.35% | | | | | | | | | | | | |