Shareholders' Equity - (Details) (USD $)	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Shareholders' Equity
Employee Stock Purchase Plan (ESPP): Maximum annual contribution per employee	10.00%
Employee Stock Purchase Plan (ESPP), Shares authorized			250,000
Employee Stock Purchase Plan (ESPP), Shares in ESPP	218,000
Employee Stock Purchase Plan (ESPP), Shares purchased	24,000	19,000	19,000
Employee Stock Purchase Plan (ESPP), Weighted average purchase price	$ 13.35	$ 19.72	$ 15.29
Preferred stock, shares authorized	2,500,000	2,500,000
Preferred stock, par or stated value per share	$ 0.01	$ 0.01
Stock Employee Compensation Trust (SECT) [Member]
Shareholders' Equity
Stock Trusts, Shares held	3,304,000	3,304,000	3,304,000
Omnibus Stock Trust (OST) [Member]
Shareholders' Equity
Stock Trusts, Shares held	59,000	59,000	59,000