Compensation Plans (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012	Sep. 25, 2014
Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]
Options outstanding, in shares at beginning	4,000
Options exercised, in shares	(4,000)
Options outstanding, in shares at end	0	4,000
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	$ 33.03
Options exercised, weighted average exercise price (in dollars per share)	$ 33.03
Options outstanding, weighted average exercise price (in dollars per share), at end		$ 33.03
Share-based Compensation Arrangement by Share-based Payment Award, Options, Additional Disclosures [Abstract]
Options outstanding, aggregate intrinsic value	$ 262,890
Market price of common stock (in dollars per share)				$ 98.75
Proceeds from exercise of stock options	$ 130,000	$ 29,000	$ 12,000