Aggregate notional amount specified by the derivative(s). Expressed as an absolute value.

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-Publisher SEC
-Name Regulation S-X (SX)
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Accumulated change in equity from transactions and other events and circumstances from non-owner sources, net of tax effect, at period end. Excludes Net Income (Loss), and accumulated changes in equity from transactions resulting from investments by owners and distributions to owners. Includes foreign currency translation items, certain pension adjustments, unrealized gains and losses on certain investments in debt and equity securities, other than temporary impairment (OTTI) losses related to factors other than credit losses on available-for-sale and held-to-maturity debt securities that an entity does not intend to sell and it is not more likely than not that the entity will be required to sell before recovery of the amortized cost basis, as well as changes in the fair value of derivatives related to the effective portion of a designated cash flow hedge.

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

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Cap rate on an interest rate derivative such as an interest rate cap or collar. If market rates exceed the cap rate, a payment or receipt is triggered on the contract.

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Fixed interest rate related to the interest rate derivative.

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The number of derivative instruments of a particular group held by the entity.

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The estimated net amount of unrealized gains or losses on foreign currency cash flow hedges at the reporting date expected to be reclassified to earnings within the next 12 months.

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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.

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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.

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Number of interest rate derivative instruments held by the entity at the reporting date.

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Derivative Financial Instruments Narrative (Details)	1 Months Ended	12 Months Ended
Derivative Financial Instruments Narrative (Details)	Jan. 31, 2019 USD ($)	Dec. 31, 2015 USD ($)	Jun. 30, 2019 USD ($) contracts	Dec. 31, 2018 USD ($)	Jun. 30, 2018 USD ($)	Apr. 30, 2018 USD ($)	Dec. 31, 2017 USD ($)
Net unrealized loss on hedging instruments			$ 194,349,000	$ 196,305,000
Total debt			615,625,000
Debt Instrument, interest rate, stated percentage						1.38%
Secured Debt [Member]
Total debt			1,015,625,000	1,037,813,000
Accumulated Other Comprehensive Income, Net Unrealized Gain (Loss) on Nonderivative Instruments [Member]
Net unrealized loss on hedging instruments			$ 14,380,000	$ 14,380,000	$ 14,380,000		$ 14,380,000
Number of Counterparties [Member]
Derivative counterparties			6	5
Interest Rate Swap [Member]
Number of interest rate derivatives held			1
Derivative, notional amount			$ 214,000,000
Pay fixed interest rate in interest rate swap			1.42%
Interest rate cash flow hedge gain (loss) to be reclassified during next 12 months, net			$ 700,000
Interest Rate Cap [Member]
Number of interest rate derivatives held			3
Derivative, notional amount		$ 100,000,000	$ 100,000,000
Interest rate cash flow hedge gain (loss) to be reclassified during next 12 months, net			$ (600,000)
Derivative purchase price		$ 1,700,000
Derivative, cap interest rate			2.00%
Currency Swap [Member]
Derivative, notional amount						$ 56,000,000.0
Foreign currency cash flow hedge gain (loss) to be reclassified during next 12 months						$ 1,300,000
Foreign Exchange Option [Member]
Derivative, notional amount	$ 72,000,000
Derivative purchase price	$ 1,300,000
Forward Contracts [Member]
Number of foreign exchange contracts \| contracts			48
Foreign Exchange Contract [Member] \| Not Designated as Hedging Instrument [Member] \| Minimum [Member]
Derivative, notional amount			$ 131,000
Foreign Exchange Contract [Member] \| Not Designated as Hedging Instrument [Member] \| Maximum [Member]
Derivative, notional amount			9,400,000
London Interbank Offered Rate (LIBOR) [Member] \| Secured Debt [Member]
Total debt			$ 615,600,000