Share-Based Compensation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2011	Jun. 30, 2010	Jun. 30, 2011	Jun. 30, 2010	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Nonvested, beginning of period (in shares)	292,650		292,650		187,140
Nonvested, end of period (in shares)	292,650		292,650		187,140
Share-based compensation expense	$ 396	$ 632	$ 1,456	$ 1,561
Share-based compensation cost capitalized as part of real estate assets	45	48	85	94
Unrecognized compensation cost related to nonvested stock awards	$ 3,448		$ 3,448
Compensation cost to be recognized over a weighted average period			3.4
Restricted stock awards (in shares)	1,000
Stock Options [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Outstanding, beginning of period (in shares)			447,825
Cancelled (in shares)			(4,400)
Exercised (in shares)			(134,500)
Outstanding, end of period (in shares)	308,925		308,925
Vested and exercisable, end of period (in shares)	308,925		308,925
Weighted average exercise price, outstanding, beginning of period (in dollars per share)					$ 16.92
Weighted average exercise price, cancelled (in dollars per share)			$ 18.04
Weighted average exercise price, exercised (in dollars per share)	$ 13.91		$ 13.91
Weighted average exercise price, outstanding, end of period (in dollars per share)					$ 16.92
Weighted average exercise price, vested and exercisable, end of period (in dollars per share)	$ 18.26		$ 18.26
Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Granted (in shares)			179,750
Vested (in shares)			(71,880)
Forfeited (in shares)			(2,360)
Weighted average grant date fair value, nonvested, beginning of period (in dollars per share)	$ 16.09		$ 16.09		$ 18.43
Weighted average grant date fair value, granted (in dollars per share)			$ 17.48
Weighted average grant date fair value, vested (in dollars per share)			$ 25.59
Weighted average grant date fair value, forfeited (in dollars per share)	$ 17.56		$ 17.56
Weighted average grant date fair value, nonvested, end of period (in dollars per share)	$ 16.09		$ 16.09		$ 18.43