Stock-Based Compensation (Details) (USD $) In Thousands, except Share data, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Fair values of options calculated based on assumptions using Black-Scholes option-pricing model
Options granted	164,500	176,250	325,000
Exercise price	$ 17.67	$ 25.18	$ 25.77
Assumptions:
Expected life in years	6 years	6 years	6 years
Risk-free interest rate	0.76%	2.30%	2.98%
Expected annual dividend yield	3.01%	2.96%	3.00%
Expected volatility	53.46%	56.25%	55.12%
Grant date fair value	$ 6.68	$ 10.53	$ 10.77
Resulting stock-based compensation expense	$ 1,099	$ 1,857	$ 3,500