Compensation Plans (Details) (USD $)	12 Months Ended
	Dec. 31, 2012		Dec. 31, 2011	Dec. 31, 2010
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, in shares at beginning	6,000
Options exercised, in shares	(1,000)	[1]
Options outstanding, in shares at end	5,000		6,000
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Roll Forward]
Options outstanding, weighted average exercise price (in dollars per share), at beginning	$ 28.86
Options exercised, weighted average exercise price (in dollars per share)	$ 12.14	[1]
Options outstanding, weighted average exercise price (in dollars per share), at end	$ 32.21		$ 28.86
Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Additional Disclosures [Abstract]
Vested, in shares at end of year	5,000
Exercisable, in shares, at end of year	5,000
Options, vested, weighted average exercise price (in dollars per share)	$ 32.21
Options, exercisable, weighted average exercise price (in dollars per share)	$ 32.21
Options outstanding, weighted average remaining contractual term (in years)	3 years
Options vested weighted average remaining contractual term (in years)	3 years
Options exercisable, weighted average remaining contractual term (in years)	3 years
Options outstanding, aggregate intrinsic value	$ 40,700	[2]
Options, vested, aggregate intrinsic value	40,700	[2]
Options exercisable, aggregate intrinsic value	40,700	[2]
Market price of common stock (in dollars per share)	$ 40.00
Proceeds from exercise of stock options	$ 12,000		$ 226,000	$ 239,000

[1] Cash received for options exercised totaled $12,140.

[2] Based on closing price at December 31, 2012 of $40.00 per share.