On November 3, 2017, we acquired the controlling interest (54.5% of the common stock) in Esja, a private corporation in Reykjavik, Iceland. Through Esja and its wholly-owned subsidiary, we are operating a FlyOver Iceland attraction.

The minority Esja shareholders have the right to sell (or “put”) their Esja shares to us based on a multiple of 5.0x EBITDA as calculated on the trailing 12 months from the most recently completed quarter before the put option exercise. The put option is only exercisable after 36 months of business operation (the “Reference Date”) and if the FlyOver Iceland attraction has earned a minimum of €3.25 million in unadjusted EBITDA during the most recent fiscal year and during the trailing 12-month period prior to exercise (the “Put Option Condition”). The put option is exercisable during a period of 12 months following the Reference Date (the “Option Period”) if the Put Option Condition has been met. If the Put Option Condition has not been met during the first Option Period, the Reference Date will be extended for an additional 12 months up to three times. If after 72 months, the FlyOver Iceland attraction has not achieved the Put Option Condition, the put option expires. If the Put Option Condition is met during any of the Option Periods, yet the shares are not exercised prior to the end of the 12-month Option Period, the put option will expire.

The noncontrolling interest’s carrying value is determined by the fair value of the noncontrolling interest as of the acquisition date and the noncontrolling interest’s share of the subsequent net income or loss. This value is benchmarked against the redemption value of the sellers’ put option. The carrying value is adjusted to the redemption value, provided that it does not fall below the initial carrying value, as determined by the purchase price allocation. We have made a policy election to reflect any changes caused by such an adjustment to retained earnings, rather than to current earnings.

(in thousands)
Balance at December 31, 2020	$	5,225
Net loss attributable to redeemable noncontrolling interest		(494	)
Adjustment to the redemption value		56
Capital contribution		142
Foreign currency translation adjustment		77
Balance at March 31, 2021	$	5,006

Non-redeemable noncontrolling interest represents the portion of equity in a subsidiary that is not attributable, directly or indirectly, to us. Our non-redeemable noncontrolling interest relates to the equity ownership interest that we do not own.

(in thousands)	Glacier Park Inc.			Brewster ⁽¹⁾			Sky Lagoon			Total
Balance at December 31, 2020	$	13,953		$	51,295		$	12,896		$	78,144
Net loss attributable to non-redeemable noncontrolling interest		(729	)		(87	)		(629	)		(1,445	)
Acquisitions		—			6,759			—			6,759
Dividends		—			(951	)		—			(951	)
Foreign currency translation adjustments		2			654			94			750
Balance at March 31, 2021	$	13,226		$	57,670		$	12,361		$	83,257
Equity ownership interest that we do not own		20	%		40	%		49	%