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Share-based compensation arrangement by share-based payment award vesting date.

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Voluntary termination of employment age limit.

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Voluntary termination of employment terms.

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Unrecognized cost of unvested share-based compensation awards.

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Weighted average period over which unrecognized compensation is expected to be recognized for equity-based compensation plans, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Period which an employee's right to exercise an award is no longer contingent on satisfaction of either a service condition, market condition or a performance condition, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

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Description of award terms as to how many shares or portion of an award are no longer contingent on satisfaction of either a service condition, market condition or a performance condition, thereby giving the employee the legal right to convert the award to shares, to sell the shares, and be entitled to the cash proceeds of such sale. For example, vesting may be expressed as being 25 percent of the shares under option on each anniversary of the grant date.

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Discount rate from fair value on purchase date that participants pay for shares.

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The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).

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The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.

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Number of options outstanding, including both vested and non-vested options.

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Number of shares (or other type of equity) issued during the period as a result of any equity-based compensation plan other than an employee stock ownership plan (ESOP), net of any shares forfeited. Shares issued could result from the issuance of restricted stock, the exercise of stock options, stock issued under employee stock purchase plans, and/or other employee benefit plans.

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Share Based Compensation, 401(k) Plan and Deferred Compensation (Textual) (Details)			12 Months Ended
	Feb. 28, 2018 Installment shares	Feb. 01, 2018 shares	Dec. 31, 2018 USD ($) shares	Dec. 31, 2017 USD ($) shares	Dec. 31, 2016 USD ($)	Feb. 09, 2018 $ / shares	Dec. 18, 2017 shares	May 18, 2017 shares	Mar. 01, 2017 shares	Feb. 22, 2016 shares
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Number \| shares			964,359	2,238,590
Share-based compensation expense			$ 7,600,000	$ 6,300,000	$ 5,600,000
Share-based compensation expense, capitalized			1,600,000	1,200,000	1,000,000.0
Defined Contribution Plan, Employer Discretionary Contribution Amount			$ 400,000	500,000	400,000
Defined Contribution Plan, Maximum Annual Contribution Per Employee, Percent			100.00%
Aggregate share-based awards awarded to executives \| shares								6,500,000
Number of shares to be issued under deferred compensation plan included in total shares outstanding \| shares			1,000,000.0				900,000
Stock Option [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense			$ 0		0
Share-based compensation expense, capitalized			0		0
Restricted Share Rights Awards [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense			3,600,000	2,800,000	2,600,000
Share-based compensation expense, capitalized			$ 600,000	$ 400,000	400,000
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number \| shares			466,439	455,643
Unrecognized compensation expenses			$ 1,800,000
Weighted average period over which options will be recognized			1 year 3 months 18 days
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			two to three years from the initial grant dates
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period \| shares			220,241
Voluntary Termination Of Employment Terms	after reaching at least age 57 and accumulating at least 15 years of service with the Company.
Accumulated Service Period For Voluntary Termination	15 years
Restricted Share Rights Awards [Member] \| Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Voluntary Termination of Employment Age Limit	57 years
Restricted Share Rights Awards [Member] \| Non-Officer Employees [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period \| shares	44,062
Number of restricted share right will get settled for common share \| shares	1
Number of Vesting Installments \| Installment	3
Restricted Share Rights Awards [Member] \| Cliff Vest [Member] \| Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period \| shares	134,487
Share Based Compensation Arrangement By Share Based Payment Award, Vesting Date	Apr. 15, 2021
Restricted Share Rights Awards [Member] \| Installment One [Member] \| Non-Officer Employees [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award, Vesting Date	Apr. 15, 2019
Restricted Share Rights Awards [Member] \| Installment Two [Member] \| Non-Officer Employees [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award, Vesting Date	Apr. 15, 2020
Restricted Share Rights Awards [Member] \| Share-based Compensation Award, Tranche Three \| Non-Officer Employees [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share Based Compensation Arrangement By Share Based Payment Award, Vesting Date	Apr. 15, 2021
Restricted Share Rights Awards [Member] \| Maximum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			3 years
Restricted Share Rights Awards [Member] \| Minimum [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Vesting period			2 years
Restricted Performance Share Units Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense			$ 3,900,000	$ 3,400,000	2,800,000
Share-based compensation expense, capitalized			1,100,000	$ 800,000	600,000
Unrecognized compensation expenses			$ 2,000,000.0
Weighted average period over which options will be recognized			1 year 1 month 6 days
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period				three-year
Common shares issued for share based compensation \| shares		193,516
Dividends Payable, Amount Per Share \| $ / shares						$ 0.18
Restricted Performance Share Units Plan [Member] \| Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number \| shares			600,273	400,488
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period \| shares			209,193
Aggregate share-based awards awarded to executives \| shares	209,193								174,854	231,388
Restricted Performance Share Units Plan [Member] \| Cliff Vest [Member] \| Executive Officer [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Rights			three year cliff vesting period
Employee Share Purchase Plan [Member]
Share Based Compensation Arrangement By Share Based Payment Award [Line Items]
Share-based compensation expense			$ 100,000	$ 100,000	200,000
Share purchases made by employees under ESPP			85% of the average closing price per share for a specified period
Maximum participant contribution, percentage of compensation			20.00%
Maximum participant contribution, dollar amount			$ 50,000
Aggregate share-based awards awarded to executives \| shares			1,250,000
Stock Issued During Period, Value, Employee Stock Purchase Plan			$ 500,000	$ 400,000	$ 400,000
Share-based Compensation Arrangement by Share-based Payment Award, Discount from Market Price, Purchase Date			15.00%