Summary of Significant Accounting Policies (Details 4) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Weighted-average shares outstanding - Basic:
Common stock	32,142	32,624	32,537
Participating restricted stock	17	189	543
Total	32,159	32,813	33,080
Weighted-average shares outstanding - Diluted:
Common stock	32,459	32,833	32,822
Participating restricted stock	17	189	543
Total	32,476	33,022	33,365