The following table summarizes the aggregate notional amount and estimated net fair value of our derivative instruments as of December 31, 2020 and 2019:

	As of December 31, 2020						As of December 31, 2019
	Notional		Fair Value of Assets		Fair Value of Liabilities		Notional		Fair Value of Assets		Fair Value of Liabilities
Cash flow hedges:
Interest rate swap	$	150,000	$	—		694	$	150,000	$	953	$	—
Interest rate collars		250,000		—		13,331		250,000		—		4,330
Forward interest rate swaps		—		—		15,817		—		—		3,439
Total	$	400,000	$	—		29,842	$	400,000	$	953	$	7,769

On June 24, 2016, we entered into an interest rate swap contract with a notional value of $150,000, a strike rate of 1.145% and a maturity date of June 17, 2021. We designated this interest rate swap as a cash flow hedge at inception and determined that the hedge is highly effective in offsetting interest rate fluctuations associated with the identified indebtedness. We did not recognize any ineffectiveness associated with this cash flow hedge through April 2017. On April 17, 2017, in conjunction with the refinancing of our credit facility, we restructured our existing interest rate swap to remove the LIBOR floor. This resulted in a decrease in the strike rate to 1.1325%. The notional value and maturity date remained the same. We designated the restructured interest rate swap as a cash flow hedge at inception and determined that the hedge is highly effective in offsetting interest rate fluctuations associated with the identified indebtedness. Upon our early adoption of accounting standard updates to ASC Topic 815, “Derivatives and Hedging,” ineffectiveness is no longer measured or reported.

On October 17, 2018, we purchased an interest rate collar with an initial notional value of $100,000, a 2.50% cap and 2.25% floor, and a maturity date of January 17, 2024. The notional value was adjusted to $150,000 in November 2018. We designated this interest rate collar as a cash flow hedge at inception and determined that the hedge is highly effective in offsetting interest rate fluctuations associated with the identified indebtedness. We concluded that this hedging relationship was and will continue to be highly effective using the hypothetical derivative method.

On November 17, 2017, we purchased an interest rate collar with a notional value of $100,000, a 2.00% cap and 1.25% floor, and a maturity date of November 17, 2024. We designated $50,000 of the interest rate collar as a cash flow hedge at inception and determined that the hedge is highly effective in offsetting interest rate fluctuations associated with the identified indebtedness. We concluded that this hedging relationship was and will continue to be highly effective using the hypothetical derivative method.

The other $50,000 notional value interest rate collar was accounted for as a freestanding derivative from inception. On January 4, 2018, we designated this other $50,000 notional value interest rate collar as a cash flow hedge and determined that the hedge is highly effective in offsetting interest rate fluctuations associated with the identified indebtedness. We concluded that this hedging relationship was and will continue to be highly effective using the hypothetical derivative method.

On March 2, 2020, we entered into a forward-starting interest rate swap with a notional value of $150,000 and a strike rate of 0.985%. This forward interest rate swap has an effective date of May 17, 2022 and a maturity date of May 17, 2027. We designated this forward interest rate swap as a cash flow hedge at inception and determined that the hedge is highly effective in offsetting interest rate fluctuations associated with the identified indebtedness.

On May 9, 2019, we entered into a forward-starting interest rate swap contract with a notional value of $150,000 and a strike rate of 2.176%. The forward interest rate swap has an effective date of June 17, 2021 and a maturity date of June 17, 2026. We designated this forward interest rate swap as a cash flow hedge at inception and determined that the hedge is highly effective in offsetting interest rate fluctuations associated with the identified indebtedness.

Effective interest rate swaps and collars are reported in accumulated other comprehensive income (loss) and the fair value of these hedge agreements is included in other assets or other liabilities.

For interest rate swaps and collars that are considered effective hedges, we reclassified realized gains (losses) of ($5,352), $1,139 and $1,372 to earnings within interest expense for the years ended December 31, 2020, 2019 and 2018, respectively. For interest rate swaps that are considered effective hedges, we expect ($7,934) to be reclassified out of accumulated other comprehensive income (loss) to earnings over the next 12 months.