Share-Based Compensation (Details) (USD $) In Thousands, except Per Share data, unless otherwise specified	3 Months Ended		6 Months Ended		3 Months Ended	6 Months Ended			6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012 Restricted Stock Five Year Vesting Period [Member]	Jun. 30, 2012 Stock Options [Member]	Jun. 30, 2011 Stock Options [Member]	Dec. 31, 2011 Stock Options [Member]	Jun. 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	$ 729	$ 396	$ 1,756	$ 1,456
Share-based compensation cost capitalized as part of real estate assets	30	45	51	85
Unrecognized compensation cost related to nonvested stock awards	$ 4,987		$ 4,987
Compensation cost to be recognized over a weighted average period			3 years 10 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)									402,960	289,290
Granted (in shares)									208,250
Vested (in shares)									(86,590)
Forfeited (in shares)									(7,990)
Nonvested, end of period (in shares)									402,960	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)									$ 18.35
Weighted average grant date fair value, vested (in dollars per share)									$ 16.70
Weighted average grant date fair value, forfeited (in dollars per share)									$ 16.69
Weighted average grant date fair value, nonvested, end of period (in dollars per share)									$ 17.11	$ 16.09
Stock Issued During Period, Shares, Restricted Stock Award, Gross					2,500
Share-based Compensation Arrangement by Share-based Payment Award, Award Vesting Period			5 years