|
Stock Awards (Narrative) (Details) (USD $)
|
12 Months Ended |
|
Dec. 31, 2010
|
Dec. 31, 2009
|
Dec. 31, 2008
|
Dec. 31, 2007
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Reserved shares of common stock for awards under the Equity Incentive Plan |
7,441,180 |
|
|
|
| Common stock remaining for future stock awards |
3,716,379 |
|
|
|
| Maximum number of shares of common stock that may be awarded |
1,000,000 |
|
|
|
| Stock award vesting period (in years) |
ten |
|
|
four |
| Number of stock options awarded |
|
|
|
50,000 |
| Stock award payment award, exercise price, per share |
|
|
|
$ 12.09 |
| Stock award payment award, estimated grant date fair value, per share |
|
|
|
$ 1.36 |
| Share based payment award, expiration period |
|
|
|
2012 |
| Share based payment award, expected volatility rate |
|
|
|
28.34% |
| Share based payment award, weighted average risk-free rate of return |
|
|
|
4.62% |
| Common stock options awarded, dividend yield |
|
|
|
8.93% |
| Common stock options awarded, intrinsic value of options exercisable and outstanding |
$ 0 |
|
|
|
| Common stock options awarded, options outstanding and exercisable |
130,000 |
|
|
|
| Common stock options awarded, weighted-average exercise price, per option |
$ 10.80 |
|
|
|
| Common stock options awarded, weighted average remaining contractual term (in years) |
3.0 |
|
|
|
| Stock award vesting period in years, maximum |
seven |
|
|
|
| Stock award vesting period in years, minimum |
three |
|
|
|
| Percentage of shareholder return annually |
9.50% |
|
|
|
| Percentage of shareholder return annually achieving period (in years) |
3 |
|
|
|
| Percentage of SPRE awards earned when the Company performed at or above the 50th percentile of real estate trusts included in the Morgan Stanley REIT Index in terms of return to shareholders |
33.334% |
|
|
|
| Percentage of superior performance awards deemed forfeited |
66.666% |
|
|
|
| Percentage of dividend per share |
20.00% |
|
|
|
| Common share distribution |
|
$ 1.13 |
$ 1.10 |
$ 1.08 |
| Percentage of increase in dividend per share |
|
3.00% |
|
|
| Stock-based compensation expense |
6,600,000 |
5,500,000 |
6,400,000 |
|
| Stock-based compensation expense, unrecognized cost |
9,600,000 |
|
|
|
| Stock-based compensation expense, unrecognized cost, weighted average period (in years) |
2.4 |
|
|
|
| Restricted equity awards, fair value |
$ 6,100,000 |
|
|
|
|
Time-Based Awards [Member]
|
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Stock award vesting period (in years) |
|
|
|
three |
| Stock award vesting period in years, maximum |
seven |
|
|
|
| Stock award vesting period in years, minimum |
three |
|
|
|
|
Service-Based Awards [Member]
|
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Stock award vesting period (in years) |
|
|
|
seven |
|
Superior Performance Awards [Member]
|
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Stock award vesting period (in years) |
three |
|
|
|
| Share based payment award, expected volatility rate |
27.00% |
|
|
|
| Share based payment award, weighted average risk-free rate of return |
4.55% |
|
|
|
| Share-based compensation arrangement by share based payment award, expected term (in years) |
3.4 |
|
|
|
|
Core Performance Awards [Member]
|
|
|
|
|
| Share-based Compensation Arrangement by Share-based Payment Award [Line Items] |
|
|
|
|
| Stock award vesting period (in years) |
|
|
|
seven |
| Number of stock options awarded |
79,287 |
79,287 |
|
|
| Share based payment award, expected volatility rate |
26.00% |
|
|
|
| Share based payment award, weighted average risk-free rate of return |
4.65% |
|
|
|
| Percentage of shareholder return annually |
|
|
|
9.00% |
| Percentage of shareholder return on a prorated basis |
|
|
|
7.50% |
| Share-based compensation arrangement by share based payment award, expected term (in years) |
6.4 |
|
|
|