Shareholders' capital - Preferred Shares (Detail) $ / shares in Units, $ in Thousands, $ in Thousands	Dec. 31, 2023 USD ($) shares	Dec. 31, 2023 CAD ($) $ / shares shares	Dec. 31, 2022 USD ($)
Stockholders Equity Note [Line Items]
Preferred shares \| $	$ 184,299		$ 184,299
Series A Shares
Stockholders Equity Note [Line Items]
Preferred stock issued (in shares) \| shares	4,800,000	4,800,000
Shares issued, price per share (USD and CAD per share) \| $ / shares		$ 25
Preferred shares	$ 100,463	$ 116,546
Series D Shares
Stockholders Equity Note [Line Items]
Preferred stock issued (in shares) \| shares	4,000,000	4,000,000
Shares issued, price per share (USD and CAD per share) \| $ / shares		$ 25
Preferred shares	$ 83,836	$ 97,259

Aggregate par or stated value of issued nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer). This item includes treasury stock repurchased by the entity. Note: elements for number of nonredeemable preferred shares, par value and other disclosure concepts are in another section within stockholders' equity.

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 852
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 10
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147481372/852-10-55-10

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 944
-SubTopic 210
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.7-03(a)(21))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479440/944-210-S99-1

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
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