Stock-Based Compensation Plans (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Stock-based compensation expense
Total stock-based compensation	$ 8,385	$ 6,859	$ 8,969
Employee [Member]
Stock-based compensation expense
Total stock-based compensation	7,714	6,180	8,316
Non-employee directors [Member]
Stock-based compensation expense
Total stock-based compensation	671	679	653
Restricted stock and performance shares [Member] | Employee [Member]
Stock-based compensation expense
Total stock-based compensation	7,046	5,856	6,588
Stock options [Member] | Employee [Member]
Stock-based compensation expense
Total stock-based compensation	668	324	1,728
Stock options [Member] | Non-employee directors [Member]
Stock-based compensation expense
Total stock-based compensation			83
Restricted stock [Member] | Non-employee directors [Member]
Stock-based compensation expense
Total stock-based compensation	$ 671	$ 679	$ 570