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Equity-Based Compensation (Narrative) (Details) $ / shares in Units, $ in Thousands | 1 Months Ended | 12 Months Ended |
--- | --- | --- | ---
Jan. 31, 2016 $ / shares shares | Dec. 31, 2015 USD ($) $ / shares shares | Jun. 30, 2015 shares | Jun. 30, 2014 USD ($) shares | Jan. 31, 2014 USD ($) shares | Jan. 31, 2013 USD ($) shares | Dec. 31, 2015 USD ($) payment $ / shares shares | Dec. 31, 2014 $ / shares shares | Dec. 31, 2013 $ / shares shares | May. 07, 2015 shares
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Typical vesting period, in years |  |  |  |  |  |  | 4 years |  |  |
Number of shares available for issuance under the Plan |  | 691,000 |  |  |  |  | 691,000 |  |  |
Granted |  |  |  |  |  |  | 37,500 | 0 | 0 |
Number of restricted stock units credited to participant accounts |  |  |  |  |  |  | 519,668 | 647,371 |  |
Market price of common stock, per share | $ / shares |  | $ 25.44 |  |  |  |  | $ 25.44 |  |  |
Requisite vesting age |  |  |  |  |  |  | 60 years |  |  |
Intrinsic value of options exercisable | $ |  | $ 4,065 |  |  |  |  | $ 4,065 |  |  |
Weighted average remaining life of options exercisable |  |  |  |  |  |  | 3 years 5 months 1 day |  |  |
Unrecognized compensation cost | $ |  | $ 12,479 |  |  |  |  | $ 12,479 |  |  |
Weighted average cost recognition period, in years |  |  |  |  |  |  | 2 years 9 months 18 days |  |  |
Performance Stock Units |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Percentage of target performance stock units earned |  |  |  |  |  |  |  |  | 50.00% |
Targeted performance stock units |  |  |  |  |  |  |  |  | 237,000 |
Performance stock units outstanding |  | 237,000 |  |  |  |  | 237,000 |  |  |
Shares awarded |  |  |  | 19,000 | 212,000 | 304,000 |  |  |  |
Performance stock unit grant-date fair value | $ |  |  |  | $ 319 | $ 3,914 | $ 4,123 |  |  |  |
Performance stock units earned |  |  |  |  |  |  |  |  | 114,000 |
Service period |  |  |  |  |  |  | 5 years |  |  |
Closing price period for determination of cash conversion |  |  |  |  |  |  | 90 days |  |  |
Management Stock Purchase Plan |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Closing price period for determination of cash conversion |  |  |  |  |  |  | 200 days |  |  |
Weighted average fair value of per unit awarded | $ / shares |  |  |  |  |  |  | $ 19.95 | $ 15.68 |  |
Number of restricted stock units credited to participant accounts |  |  |  |  |  |  | 94,047 | 119,105 | 132,037 |
Accrues interest |  |  |  |  |  |  | 2.00% |  |  |
Lump sum payment option one | payment |  |  |  |  |  |  | 1 |  |  |
Lump sum payment option two | payment |  |  |  |  |  |  | 5 |  |  |
Lump sum payment option three | payment |  |  |  |  |  |  | 10 |  |  |
Maximum | Performance Stock Units |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Performance stock unit vesting period |  |  |  |  |  |  | 3 years |  |  |
Minimum | Performance Stock Units |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Performance stock unit vesting period |  |  |  |  |  |  | 1 year |  |  |
Performance Shares |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Performance stock units outstanding |  | 396,714 |  |  |  |  | 396,714 | 0 |  |
Shares awarded |  |  |  |  |  |  | 396,714 | 0 | 0 |
Weighted average fair value of per unit awarded | $ / shares |  |  |  |  |  |  | $ 19.78 | $ 0.00 | $ 0.00 |
Unvested Restricted Stock Units |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Number of restricted stock units credited to participant accounts |  |  |  |  |  |  | 59,091 | 62,455 |  |
2015 Equity Incentive Plan |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Maximum number of shares that may be issued under the Plan |  |  |  |  |  |  |  |  |  | 1,250,000
2015 Equity Incentive Plan | Performance Shares |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award, Award Performance Period |  | 3 years |  |  |  |  |  |  |  |
Shares awarded |  | 75,000 | 321,714 |  |  |  |  |  |  |
2015 Equity Incentive Plan | Performance Shares | Subsequent Event [Member] |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Percentage of target performance stock units earned | 200.00% |  |  |  |  |  |  |  |  |
Targeted performance stock units | 219,000 |  |  |  |  |  |  |  |  |
Shares awarded | 219,000 |  |  |  |  |  |  |  |  |
Performance stock units earned | 438,000 |  |  |  |  |  |  |  |  |
Weighted average fair value of per unit awarded | $ / shares | $ 4,039,000 |  |  |  |  |  |  |  |  |
2005 Equity Incentive Plan |  |  |  |  |  |  |  |  |  |
Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |  |  |  |  |  |  |  |  |  |
Maximum number of shares that may be issued under the Plan |  |  |  |  |  |  |  |  |  | 274,374

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