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.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(22))
-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 944
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(16))
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Reference 3: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 942
-SubTopic 210
-Section S99
-Paragraph 1
-Subparagraph (SX 210.9-03(16))
-URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878

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Balance Type:	credit
Period Type:	instant

- Definition

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

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 55
-Paragraph 8
-URI http://asc.fasb.org/extlink&oid=64930739&loc=d3e28878-108400

Reference 2: http://www.xbrl.org/2003/role/presentationRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 835
-SubTopic 30
-Section 45
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28551-108399

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Period Type:	instant

- Definition

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

+ References

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- Definition

Amount of stock repurchase plan authorized.

+ References

No definition available.

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Balance Type:	credit
Period Type:	instant

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

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Subsequent events (Details) - USD ($)	Aug. 09, 2018	Aug. 01, 2018	Jun. 30, 2018	Dec. 31, 2017
Subsequent Event [Line Items]
Debt outstanding			$ 705,877,000	$ 709,470,000
Term Loan B
Subsequent Event [Line Items]
Debt outstanding			$ 705,877,000	$ 709,470,000
Subsequent event
Subsequent Event [Line Items]
Stock repurchase program, authorized amount	$ 500,000,000
Subsequent event \| Term Loan B
Subsequent Event [Line Items]
Debt outstanding		$ 705,877,000
Securitized Financing Facility \| Subsequent event \| Senior fixed-rate term notes \| Fixed Rate Senior Secured Notes, Class A-2-I
Subsequent Event [Line Items]
Fixed interest rate		4.262%
Debt face amount		$ 575,000,000
Securitized Financing Facility \| Subsequent event \| Senior fixed-rate term notes \| Fixed Rate Senior Secured Notes, Class A-2-II
Subsequent Event [Line Items]
Fixed interest rate		4.666%
Debt face amount		$ 625,000,000
Securitized Financing Facility \| Subsequent event \| Variable funding notes
Subsequent Event [Line Items]
Debt face amount		$ 75,000,000