Share-Based Compensation (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		9 Months Ended					9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012 Stock Options [Member]	Sep. 30, 2011 Stock Options [Member]	Dec. 31, 2011 Stock Options [Member]	Sep. 30, 2012 Stock Awards [Member]	Dec. 31, 2011 Stock Awards [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Share-based compensation expense	$ 467	$ 252	$ 1,974	$ 1,708
Share-based compensation cost capitalized as part of real estate assets	45	52	96	137
Unrecognized compensation cost related to nonvested stock awards	$ 4,506		$ 4,506
Compensation cost to be recognized over a weighted average period			3 years 6 months
Outstanding, beginning of period (in shares)					281,725
Expired (in shares)					(15,375)	0
Exercised (in shares)					(265,350)
Outstanding, end of period (in shares)					1,000
Vested and exercisable, end of period (in shares)					1,000
Weighted average exercise price, outstanding, beginning of period (in dollars per share)					$ 19.90		$ 18.27
Weighted average exercise price, exercised (in dollars per share)					$ 18.27
Weighted average exercise price, outstanding, end of period (in dollars per share)					$ 19.90		$ 18.27
Weighted average exercise price, vested and exercisable, end of period (in dollars per share)					$ 19.90
Nonvested, beginning of period (in shares)								401,400	289,290
Granted (in shares)								208,250
Vested (in shares)								(86,900)
Forfeited (in shares)								(9,240)
Nonvested, end of period (in shares)								401,400	289,290
Weighted average grant date fair value, nonvested, beginning of period (in dollars per share)								$ 17.11	$ 16.09
Weighted average grant date fair value, granted (in dollars per share)								$ 18.36
Weighted average grant date fair value, vested (in dollars per share)								$ 16.79
Weighted average grant date fair value, forfeited (in dollars per share)								$ 16.66
Weighted average grant date fair value, nonvested, end of period (in dollars per share)								$ 17.11	$ 16.09