Debt Instrument, Derivative Instrument Basis Fixed Rate

No definition available.

Name:	adc_DebtInstrumentDerivativeInstrumentBasisFixedRate
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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

The number of times entity can extend the maturity date under the credit facility.

+ References

No definition available.

+ Details

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Namespace Prefix:	adc_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	duration

- Definition

The loss amount to be reimbursed per a contract

+ References

No definition available.

+ Details

Name:	adc_ReimbursementAgreementAmount
Namespace Prefix:	adc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
-Paragraph 4
-Subparagraph (b)(1)
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-Name Accounting Standards Codification
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount of assets pledged to secure a debt instrument.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 470
-Section 50
-Paragraph 3
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=75038535&loc=d3e64711-112823

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

The reference rate for the variable rate of the debt instrument, such as LIBOR or the US Treasury rate and the maturity of the reference rate used, such as three months or six months LIBOR.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Effective interest rate for the funds borrowed under the debt agreement considering interest compounding and original issue discount or premium.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
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-Paragraph 6
-Subparagraph (a)
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Contractual interest rate for funds borrowed, under the debt agreement.

+ References

+ Details

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Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

+ Details

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Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The percentage points added to the reference rate to compute the variable rate on the interest rate derivative.

+ References

No definition available.

+ Details

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Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

The carrying value as of the balance sheet date of the current and noncurrent portions of long-term obligations drawn from a line of credit, which is a bank's commitment to make loans up to a specific amount. Examples of items that might be included in the application of this element may consist of letters of credit, standby letters of credit, and revolving credit arrangements, under which borrowings can be made up to a maximum amount as of any point in time conditional on satisfaction of specified terms before, as of and after the date of drawdowns on the line. Includes short-term obligations that would normally be classified as current liabilities but for which (a) postbalance sheet date issuance of a long term obligation to refinance the short term obligation on a long term basis, or (b) the enterprise has entered into a financing agreement that clearly permits the enterprise to refinance the short-term obligation on a long term basis and the following conditions are met (1) the agreement does not expire within 1 year and is not cancelable by the lender except for violation of an objectively determinable provision, (2) no violation exists at the BS date, and (3) the lender has entered into the financing agreement is expected to be financially capable of honoring the agreement.

+ References

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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

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.

+ References

+ Details

Name:	us-gaap_LineOfCreditFacilityMaximumBorrowingCapacity
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 470
-SubTopic 20
-Section 50
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+ Details

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Weighted average interest rate of long-term debt outstanding calculated at point in time.

+ References

No definition available.

+ Details

Name:	us-gaap_LongtermDebtWeightedAverageInterestRate
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_CreditFacilityAxis=us-gaap_RevolvingCreditFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_MortgagesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_LongtermDebtTypeAxis=us-gaap_UnsecuredDebtMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=adc_SeniorUnsecuredNote2025Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=adc_SeniorUnsecuredNote2027Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=adc_SeniorUnsecuredNote2028Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=adc_SeniorUnsecuredNote2029Member
Namespace Prefix:
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Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=adc_SeniorUnsecuredNote2030Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=adc_SeniorUnsecuredNote2031Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=adc_RevolvingCreditAndTermLoanFacilityMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=adc_TermLoan2019Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_LondonInterbankOfferedRateLIBORMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=adc_TermLoan2023Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_DerivativeInstrumentRiskAxis=us-gaap_InterestRateSwapMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
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Balance Type:
Period Type:

- Details

Name:	us-gaap_DebtInstrumentAxis=adc_TermLoan2024Member
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Balance Type:
Period Type:

- Details

Name:	us-gaap_VariableRateAxis=us-gaap_FederalFundsEffectiveSwapRateMember
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Name:	us-gaap_VariableRateAxis=us-gaap_EurodollarMember
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- Details

Name:	us-gaap_VariableRateAxis=us-gaap_BaseRateMember
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- Details

Name:	us-gaap_DebtInstrumentAxis=adc_TwoThousandTwentyFourTermLoanFacilityOneMember
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Name:	us-gaap_DebtInstrumentAxis=adc_TermLoan2026Member
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- Details

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Debt - Narrative (Details) $ in Thousands	1 Months Ended			12 Months Ended
Debt - Narrative (Details) $ in Thousands	Dec. 31, 2018 USD ($)	Aug. 31, 2016 USD ($)	Jul. 31, 2016 USD ($)	Dec. 31, 2019 USD ($) item	Dec. 31, 2018 USD ($)	Oct. 31, 2019 USD ($)	Mar. 31, 2019 USD ($)	Sep. 30, 2018 USD ($)	Sep. 30, 2017 USD ($)	May 31, 2015 USD ($)	Nov. 18, 2014 USD ($)
Debt Instrument [Line Items]
Long-term Debt, Gross				$ 876,100
Long-term Line of Credit	$ 19,000			89,000	$ 19,000
Maximum [Member]
Debt Instrument [Line Items]
Reimbursement Agreement, Amount											$ 14,000
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross				89,000
Mortgages [Member]
Debt Instrument [Line Items]
Long-term Debt, Total	60,926			36,698	60,926
Long-term Debt, Gross	$ 61,519			37,115	$ 61,519
Debt Instrument, Collateral Amount				$ 48,400
Long-term Debt, Weighted Average Interest Rate	4.13%			4.40%	4.13%
Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Total	$ 256,419			$ 237,403	$ 256,419
Long-term Debt, Gross	258,543			240,000	258,543
Unsecured Debt [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility, Maximum Borrowing Capacity				$ 500,000
Unsecured Debt [Member] \| 2025 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage				4.16%
Unsecured Debt [Member] \| 2027 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage										4.26%
Debt Instrument, Face Amount										$ 50,000
Unsecured Debt [Member] \| 2028 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage				4.42%
Unsecured Debt [Member] \| 2029 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage				4.19%
Unsecured Debt [Member] \| 2030 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount								$ 125,000
Unsecured Debt [Member] \| 2031 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage						4.47%
Debt Instrument, Face Amount						$ 125,000
Unsecured Debt [Member] \| Revolving Credit and Term Loan Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 600,000
Unsecured Debt [Member] \| 2019 Term Loan [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	18,543				18,543
Debt Instrument, Derivative Instrument Basis Fixed Rate		1.92%
Debt Instrument, Face Amount		$ 20,300
Unsecured Debt [Member] \| 2019 Term Loan [Member] \| LIBOR
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis				Borrowings under the 2019 Term Loan were priced at LIBOR plus 170 basis points. In order to fix LIBOR on the 2019 Term Loan at 1.92% until maturity, the Company had an interest rate swap agreement in place, which was assigned by the lender under the Mortgage Note to the 2019 Term Loan lender
Spread on variable rate		1.70%
Unsecured Debt [Member] \| 2023 Term Loan [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	40,000			$ 40,000	40,000
Debt Instrument, Description of Variable Rate Basis				Borrowings under the 2023 Term Loan are priced at LIBOR plus 85 to 165 basis points, depending on the Company’s credit rating. The Company entered into an interest rate swap agreement to fix LIBOR at 140 basis points until maturity
Debt Instrument, Interest Rate, Effective Percentage				2.40%
Debt Instrument, Face Amount			$ 40,000
Unsecured Debt [Member] \| 2023 Term Loan [Member] \| Interest Rate Swap [Member]
Debt Instrument [Line Items]
Debt Instrument, Derivative Instrument Basis Fixed Rate			1.40%
Unsecured Debt [Member] \| 2023 Term Loan [Member] \| Minimum [Member] \| LIBOR
Debt Instrument [Line Items]
Spread on variable rate			0.85%
Unsecured Debt [Member] \| 2023 Term Loan [Member] \| Maximum [Member] \| LIBOR
Debt Instrument [Line Items]
Spread on variable rate			1.65%
Unsecured Debt [Member] \| 2024 Term Loan Facilities[Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	100,000			$ 100,000	100,000
Debt Instrument, Description of Variable Rate Basis				(i) LIBOR plus a margin that is based upon the Company's credit rating or (ii) the Base Rate (which is defined as the greater of the rate of interest as publicly announced from time to time by PNC Bank, National Association, as its prime rate, the Federal Funds Open Rate plus 0.50%, or the Daily Eurodollar Rate plus 1.0%) plus a margin that is based upon the Company’s credit rating. The margins for the 2024 Term Loan Facilities range in amount from 0.85% to 1.65% for LIBOR-based loans and 0.00% to 0.65% for Base Rate loans, depending on the Company’s credit rating. The Company has utilized existing interest rate swaps to fix LIBOR at 2.0904% through July 2021 for the $65.0 million term loan and at 2.1970% through September 2020 for the $35.0 million term loan. In October 2019, the Company entered into new interest swap agreements to fix LIBOR at 143 basis points for both the $65.0 million and $35.0 million term loans, through their 2024 maturity dates.
Unsecured Debt [Member] \| 2024 Term Loan Facilities[Member] \| Fed Funds Effective Rate Overnight Index Swap Rate [Member]
Debt Instrument [Line Items]
Spread on variable rate				0.50%
Unsecured Debt [Member] \| 2024 Term Loan Facilities[Member] \| Eurodollar [Member]
Debt Instrument [Line Items]
Spread on variable rate				1.00%
Unsecured Debt [Member] \| 2024 Term Loan Facilities[Member] \| Minimum [Member] \| LIBOR
Debt Instrument [Line Items]
Spread on variable rate				0.85%
Unsecured Debt [Member] \| 2024 Term Loan Facilities[Member] \| Minimum [Member] \| Base Rate
Debt Instrument [Line Items]
Spread on variable rate				0.00%
Unsecured Debt [Member] \| 2024 Term Loan Facilities[Member] \| Maximum [Member] \| LIBOR
Debt Instrument [Line Items]
Spread on variable rate				1.65%
Unsecured Debt [Member] \| 2024 Term Loan Facilities[Member] \| Maximum [Member] \| Base Rate
Debt Instrument [Line Items]
Spread on variable rate				0.65%
Unsecured Debt [Member] \| 2024 Term Loan Facility One [Member]
Debt Instrument [Line Items]
Long-term Line of Credit				$ 65,000		65,000
Unsecured Debt [Member] \| 2024 Term Loan Facility One [Member] \| Interest Rate Swap [Member] \| LIBOR
Debt Instrument [Line Items]
Spread on variable rate				2.0904%
Unsecured Debt [Member] \| 2024 Term Loan Facility Two [Member]
Debt Instrument [Line Items]
Long-term Line of Credit				$ 35,000		$ 35,000
Unsecured Debt [Member] \| 2024 Term Loan Facility Two [Member] \| Interest Rate Swap [Member] \| LIBOR
Debt Instrument [Line Items]
Spread on variable rate				2.197%
Unsecured Debt [Member] \| 2026 Term Loan [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	100,000			$ 100,000	$ 100,000
Debt Instrument, Description of Variable Rate Basis					Borrowings under the 2026 Term Loan are priced at LIBOR plus 145 to 240 basis points, depending on the Company’s credit rating. The Company entered into interest rate swap agreements to fix LIBOR at 266 basis points until maturity
Debt Instrument, Interest Rate, Effective Percentage				4.26%
Debt Instrument, Face Amount	$ 100,000				$ 100,000
Unsecured Debt [Member] \| 2026 Term Loan [Member] \| Interest Rate Swap [Member] \| LIBOR
Debt Instrument [Line Items]
Derivative, spread on variable rate	2.66%				2.66%
Unsecured Debt [Member] \| 2026 Term Loan [Member] \| Minimum [Member] \| LIBOR
Debt Instrument [Line Items]
Spread on variable rate	1.45%
Unsecured Debt [Member] \| 2026 Term Loan [Member] \| Maximum [Member] \| LIBOR
Debt Instrument [Line Items]
Spread on variable rate	2.40%
Senior Unsecured Debt [Member]
Debt Instrument [Line Items]
Long-term Debt, Total	$ 384,064			$ 509,198	$ 384,064
Long-term Debt, Gross	385,000			$ 510,000	385,000
Debt Instrument, Face Amount										100,000
Senior Unsecured Debt [Member] \| Interest Rate Swap Agreement, in March 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Stated Percentage				4.41%
Debt Instrument, Face Amount				$ 100,000			$ 100,000
Senior Unsecured Debt [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Description of Variable Rate Basis				(i) LIBOR plus a margin that is based upon the Company’s credit rating, or (ii) the Base Rate (which is defined as the greater of the rate of interest as publicly announced from time to time by PNC Bank, National Association, as its prime rate, the Federal Funds Open Rate plus 0.50%, or the Daily Eurodollar Rate plus 1.0%) plus a margin that is based upon the Company’s credit rating. The margins for the Revolving Credit Facility range in amount from 0.775% to 1.450% for LIBOR-based loans and 0.00% to 0.45% for Base Rate loans, depending on the Company’s credit rating. The margins for the Revolving Credit Facility are subject to improvement based on the Company’s leverage ratio, provided its credit rating meets a certain threshold.
Debt Instrument, Face Amount				$ 500,000
Senior Unsecured Debt [Member] \| Revolving Credit Facility [Member] \| Fed Funds Effective Rate Overnight Index Swap Rate [Member]
Debt Instrument [Line Items]
Spread on variable rate				0.50%
Senior Unsecured Debt [Member] \| Revolving Credit Facility [Member] \| Eurodollar [Member]
Debt Instrument [Line Items]
Spread on variable rate				1.00%
Senior Unsecured Debt [Member] \| Revolving Credit Facility [Member] \| Minimum [Member] \| LIBOR
Debt Instrument [Line Items]
Spread on variable rate				0.775%
Senior Unsecured Debt [Member] \| Revolving Credit Facility [Member] \| Minimum [Member] \| Base Rate
Debt Instrument [Line Items]
Spread on variable rate				0.00%
Senior Unsecured Debt [Member] \| Revolving Credit Facility [Member] \| Maximum [Member] \| LIBOR
Debt Instrument [Line Items]
Spread on variable rate				1.45%
Senior Unsecured Debt [Member] \| Revolving Credit Facility [Member] \| Maximum [Member] \| Base Rate
Debt Instrument [Line Items]
Spread on variable rate				0.45%
Senior Unsecured Debt [Member] \| 2025 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	50,000			$ 50,000	50,000
Debt Instrument, Face Amount										$ 50,000
Senior Unsecured Debt [Member] \| 2027 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	50,000			50,000	50,000
Senior Unsecured Debt [Member] \| 2028 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	60,000			60,000	60,000
Debt Instrument, Face Amount			$ 60,000
Senior Unsecured Debt [Member] \| 2029 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	100,000			100,000	100,000
Debt Instrument, Face Amount									$ 100,000
Senior Unsecured Debt [Member] \| 2030 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross	$ 125,000			$ 125,000	$ 125,000
Debt Instrument, Interest Rate, Stated Percentage				4.32%
Senior Unsecured Debt [Member] \| 2031 Senior Unsecured Notes [Member]
Debt Instrument [Line Items]
Long-term Debt, Gross				$ 125,000
Senior Unsecured Debt [Member] \| 2031 Senior Unsecured Notes [Member] \| Interest Rate Swap Agreement, in March 2019 [Member]
Debt Instrument [Line Items]
Debt Instrument, Interest Rate, Effective Percentage				4.42%
Debt Instrument, Face Amount				$ 125,000
Senior Unsecured Debt [Member] \| Revolving Credit and Term Loan Facility [Member]
Debt Instrument [Line Items]
Credit facility extension times \| item				2
Senior Unsecured Debt [Member] \| 2024 Term Loan Facility One [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 65,000
Senior Unsecured Debt [Member] \| 2024 Term Loan Facility Two [Member] \| Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Debt Instrument, Face Amount				$ 35,000