Stock-Based Compensation (Details) (USD $)	12 Months Ended
	Dec. 31, 2012 Y
Descriptions of stock options plan
Number of stock option plans	3
Options
Descriptions of stock options plan
Vesting period for grants prior to February, 2009 (in years)	5
Vesting period for grants after February, 2009 (in years)	4
Expiration period (in years)	P10Y
Total SAR and RSU | Initial Equity Grant Upon Board Election
Descriptions of stock options plan
Initial equity grant value upon joining the Board (in dollars)	200,000
Total SAR and RSU | Annual Equity Grant Upon Board Re-Election
Descriptions of stock options plan
Annual equity grant value upon re-election to the Board (in dollars)	120,000
SAR
Descriptions of stock options plan
Vesting period for grants prior to February, 2009 (in years)	5
Vesting period for grants after February, 2009 (in years)	4
Expiration period (in years)	P10Y
SAR | Initial Equity Grant Upon Board Election
Descriptions of stock options plan
Vesting period for grants (in years)	4 years
Percentage of initial equity grant value awarded to non-employee directors	70.00%
Percentage of shares vesting one year after grant date	25.00%
Period after the grant date for vesting of 25% shares (in years)	1
Period after first anniversary of initial grant date over which remainder of shares vest (in years)	3
SAR | Annual Equity Grant Upon Board Re-Election
Descriptions of stock options plan
Percentage of annual equity grant value awarded to non-employee directors	70.00%
Percentage of shares vesting one year after grant date	100.00%
Period after the grant date for vesting of 100% shares (in years)	1
RSU
Descriptions of stock options plan
Proportional vesting period for remaining shares	2 years
Vesting period for grants (in years)	4 years
Requisite service period (in years)	4 years
RSU | Initial Equity Grant Upon Board Election
Descriptions of stock options plan
Vesting period for grants (in years)	4 years
Percentage of initial equity grant value awarded to non-employee directors	30.00%
Percentage of shares vesting two years after grant date	50.00%
Period after the grant date for vesting of 50% shares (in years)	2
Percentage of shares vesting four years after grant date	50.00%
Period after the grant date for vesting of remaining 50% shares (in years)	4
RSU | Annual Equity Grant Upon Board Re-Election
Descriptions of stock options plan
Percentage of annual equity grant value awarded to non-employee directors	30.00%
Percentage of shares vesting one year after grant date	100.00%
Period after the grant date for vesting of 100% shares (in years)	1