Consolidated Balance Sheets (Unaudited) (Parenthetical) - $ / shares	3 Months Ended	12 Months Ended
Mar. 31, 2019	Dec. 31, 2018
Statement Of Financial Position [Abstract]
Preferred shares, without par value
Preferred shares, shares authorized	Unlimited	Unlimited
Preferred shares, issued	1,016,000	1,016,000
Preferred shares, outstanding	1,016,000	1,016,000
Common shares, without par value
Common shares, shares authorized	Unlimited	Unlimited
Common shares, Issued	25,771,954	25,750,721
Common shares, Outstanding	25,771,954	25,750,721

Face amount per share of no-par value common stock.

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Indicates that the number of common shares permitted to be issued by an entity's charter and bylaws is unlimited. The acceptable value is "Unlimited".

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Total number of common shares of an entity that have been sold or granted to shareholders (includes common shares that were issued, repurchased and remain in the treasury). These shares represent capital invested by the firm's shareholders and owners, and may be all or only a portion of the number of shares authorized. Shares issued include shares outstanding and shares held in the treasury.

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Number of shares of common stock outstanding. Common stock represent the ownership interest in a corporation.

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Face amount per share of no-par value preferred stock nonredeemable or redeemable solely at the option of the issuer.

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Indicates that the number of nonredeemable preferred shares, or preferred stock redeemable solely at the option of the issuer, permitted to be issued by an entity's charter and bylaws is unlimited. The acceptable value is "Unlimited".

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Total number of nonredeemable preferred shares (or preferred stock redeemable solely at the option of the issuer) issued to shareholders (includes related preferred shares that were issued, repurchased, and remain in the treasury). May be all or portion of the number of preferred shares authorized. Excludes preferred shares that are classified as debt.

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Aggregate share number for all nonredeemable preferred stock (or preferred stock redeemable solely at the option of the issuer) held by stockholders. Does not include preferred shares that have been repurchased.

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