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Derivative and Other Fair Value Instruments - Additional Information (Details) | 1 Months Ended | 12 Months Ended
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Aug. 31, 2017 USD ($) DerivativeInstrument | Oct. 31, 2016 USD ($) DerivativeInstrument | May 31, 2015 USD ($) DerivativeInstrument | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($)
Derivative [Line Items] |  |  |  |  |  |
Unrealized gain (loss) on interest rate cash flow hedges, pretax, accumulated other comprehensive income (loss) |  |  |  | $ 88,600,000 | $ 113,900,000 |
Interest rate cash flow hedge gain (loss) to be reclassified during next 12 months, net |  |  |  | $ 21,200,000 |  |
Derivative instruments, gain (loss) recognized in income, ineffective portion and amount excluded from effectiveness testing, net |  |  |  |  | (74,000) | $ (3,033,000)
Forward Starting Swaps [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Proceeds from settlement of derivative instruments | $ 1,300,000 |  |  |  |  |
Forward starting swaps settled | DerivativeInstrument | 4 |  |  |  |  |
Public notes, face value | $ 400,000,000 |  |  |  |  |
Debt instrument, term | 10 years |  |  |  |  |
Derivative instruments, gain (loss) recognized in income, ineffective portion and amount excluded from effectiveness testing, net |  |  |  |  | $ (74,000) | $ (3,033,000)
2.85% Notes [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Forward starting swaps settled | DerivativeInstrument |  | 1 |  |  |  |
Payments for (proceeds from) hedge, investing activities |  | $ 4,700,000 |  |  |  |
Proceeds from issuance of unsecured debt |  | 500,000,000 |  |  |  |
Interest expense |  | 9,000 |  |  |  |
Derivative instruments, gain (loss) recognized in income, ineffective portion and amount excluded from effectiveness testing, net |  | (74,000) |  |  |  |
Charges hedge termination activities |  | $ 4,600,000 |  |  |  |
3.375% Notes [Member] |  |  |  |  |  |
Derivative [Line Items] |  |  |  |  |  |
Forward starting swaps settled | DerivativeInstrument |  |  | 9 |  |  |
Payments for (proceeds from) hedge, investing activities |  |  | $ 15,100,000 |  |  |
Proceeds from issuance of unsecured debt |  |  | 450,000,000 |  |  |
Interest expense |  |  | 1,200,000 |  |  |
Derivative instruments, gain (loss) recognized in income, ineffective portion and amount excluded from effectiveness testing, net |  |  | (30,000) |  |  |
Charges hedge termination activities |  |  | $ 13,900,000 |  |  |

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- Definition Amount recorded in accumulated other comprehensive loss that will be recognized as an increase to interest expense over the term of the note. + References No definition available. + Details
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- Definition Number of derivative instrument settled. + References No definition available. + Details
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- 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 + Details
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- Definition Period of time between issuance and maturity of debt instrument, in PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days. + References No definition available. + Details
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- Definition The portion of gains and losses (net) on derivative instruments designated and qualifying as hedging instruments representing (a) the amount of the hedge ineffectiveness and (b) the amount, if any, excluded from the assessment of hedge effectiveness. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 25 -Section 50 -Paragraph 1 -Subparagraph (a)(1),(2) -URI http://asc.fasb.org/extlink&oid=6886632&loc=d3e76258-113986 + Details
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- Definition Amount of the cost of borrowed funds accounted for as interest expense. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 20 -Section 50 -Paragraph 1 -URI http://asc.fasb.org/extlink&oid=6450988&loc=d3e26243-108391 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 3 -URI http://asc.fasb.org/extlink&oid=64930785&loc=d3e28555-108399 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 225 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-04.9) -URI http://asc.fasb.org/extlink&oid=6879574&loc=d3e536633-122882 + Details
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- Definition The estimated net amount of unrealized gains or losses on interest rate cash flow hedges as of the balance sheet date expected to be reclassified to earnings within the next twelve months. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 30 -Section 50 -Paragraph 1 -Subparagraph (c) -URI http://asc.fasb.org/extlink&oid=35736893&loc=d3e80748-113994 + Details
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- Definition The cash outflow or inflow for a financial contract that meets the hedge criteria as either a cash flow hedge, fair value hedge, or hedge of a net investment in a foreign operation. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 27 -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3581-108585 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 9 -Subparagraph (a) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3098-108585 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3095-108585 + Details
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- Definition The cash inflow from a financial contract that meets the hedge criteria as either cash flow hedge, fair value hedge or hedge of net investment in foreign operations. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 27 -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3581-108585 + Details
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- Definition The cash inflow from the issuance of long-term debt that is not secured by collateral. Excludes proceeds from tax exempt unsecured debt. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 14 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=98514028&loc=d3e3255-108585 + Details
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- Definition Amount of unrealized gain (loss) related to the increase or decrease in fair value of interest rate derivatives designated as cash flow hedging instruments, which was recorded in accumulated other comprehensive income to the extent that the cash flow hedge was determined to be effective. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 4C -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=84234895&loc=SL5624171-113959 + Details
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