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Share Based Compensation, 401(k) Plan and Deferred Compensation (Textual) (Details) |  |  | 12 Months Ended |  |  |  |  |
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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% |  |  |  |  |  |  |

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