We use derivative instruments to manage differences in the amount, timing, and duration of our known or expected cash payments related to our outstanding debt (i.e., interest rate risk). These derivatives are designated and qualify as a hedge of the exposure to variability in expected future cash flows and are therefore considered cash flow hedges. We account for derivatives in accordance with FASB ASC Topic 815, which establishes accounting and reporting standards requiring that derivative instruments be recorded on the balance sheet at fair value as either an asset or liability. The accounting for changes in the fair value of derivatives depends on the intended use of the derivative, whether we have elected to designate a derivative in a hedging relationship and apply hedge accounting, and whether the hedging relationship has satisfied the criteria necessary to apply hedge accounting. We classify cash flows from settlement of our cash flow hedges in the same category as the cash flows from the related hedged items, generally within the operating activities in the consolidated statements of cash flows. We do not use derivatives for trading or speculative purposes and currently do not have any derivatives that are not designated as hedges.

Our objectives in using interest rate derivatives are to add stability to interest expense and to manage our exposure to interest rate movements. To accomplish this objective, we primarily use interest rate swaps as part of our interest rate risk management strategy. The counterparties to the interest rate swap agreements expose us to credit risk in the event of nonperformance by such counterparties. However, at June 30, 2020, we do not anticipate nonperformance by these counterparties. Our interest rate swap agreements with each of the counterparties contain a provision whereby if we either default or are capable of being declared in default on any of our indebtedness, whether or not such default results in repayment of the indebtedness being accelerated by the lender, then we could also be declared in default on our derivative obligations.

Interest rate swaps designated as cash flow hedges involve the receipt of variable amounts from a counterparty in exchange for our making fixed-rate payments over the life of the agreements without exchange of the underlying notional amount. In May 2019, we entered into eight amortizing interest rate swap agreements, each of which matures in May 2024. Under these agreements, we receive a variable rate of interest based on LIBOR, and we pay a fixed rate of interest equal to approximately 2.2% plus a spread (see Note 10). As of June 30, 2020, these interest rate swap agreements had current notional amounts totaling $800.0 million.

We record derivatives that are designated and qualify as cash flow hedges at estimated fair value in the consolidated balance sheet, with the related gains and losses recorded in accumulated other comprehensive income or loss ("accumulated OCI") and subsequently reclassified into interest expense in the same period(s) during which the hedged transaction affects earnings. Amounts reported in accumulated OCI related to derivatives will be reclassified to interest expense as we make interest payments on our variable-rate debt. As of June 30, 2020, we expect to reclassify $15.8 million from accumulated OCI as an increase to interest expense within the next 12 months due to the scheduled payment of interest associated with our debt.

The estimated gross fair values of derivative instruments and their classification on the consolidated balance sheet at June 30, 2020 and December 31, 2019 were as follows:

(In thousands)	June 30, 2020		December 31, 2019
Liabilities:
Derivatives designated as hedging instruments:
Current portion of long-term liabilities	$	15,664	$	4,947
Other long-term liabilities		28,743		11,291
	$	44,407	$	16,238

The following table presents the effect of cash flow hedge accounting on accumulated OCI as of June 30, 2020 and 2019:

(In thousands)	For the Three Months Ended					For the Six Months Ended
Derivatives in Cash Flow Hedging Relationships	June 30, 2020			June 30, 2019		June 30, 2020			June 30, 2019
Loss related to effective portion of derivatives recognized in accumulated OCI, gross of tax effect	$	5,020		$	16,144	$	32,772		$	16,144
Gain (loss) related to effective portion of derivatives reclassified from accumulated OCI to interest expense, gross of tax effect	$	(3,482	)	$	160	$	(4,603	)	$	160