Stock-Based Compensation Plans (Narrative) (Details) (USD $)	3 Months Ended	12 Months Ended					12 Months Ended																			12 Months Ended
	Mar. 31, 2012	Dec. 31, 2012	Dec. 31, 2012 Restricted Stock [Member]	Dec. 31, 2011 Restricted Stock [Member]	Dec. 31, 2010 Restricted Stock [Member]	Dec. 31, 2009 Restricted Stock [Member]	Dec. 31, 2012 Restricted Stock [Member] Chief Executive Officer [Member]	Dec. 31, 2012 Restricted Stock Units (RSUs) [Member]		Dec. 31, 2011 Restricted Stock Units (RSUs) [Member]		Dec. 31, 2010 Restricted Stock Units (RSUs) [Member]		Dec. 31, 2012 Restricted Stock Units (RSUs) [Member] Chief Executive Officer [Member]	Dec. 31, 2012 Maximum [Member] Restricted Stock [Member]	Dec. 31, 2012 Minimum [Member] Restricted Stock [Member]	Dec. 31, 2012 Ten Year Vesting [Member]	Dec. 31, 2012 Ten Year Vesting [Member] Restricted Stock [Member]	Dec. 31, 2012 Ten Year Vesting [Member] Restricted Stock Units (RSUs) [Member]	Dec. 31, 2012 Five Year Vesting [Member]	Dec. 31, 2012 Five Year Vesting [Member] Restricted Stock [Member]	Dec. 31, 2012 1992 Plan [Member]	Dec. 31, 2011 1992 Plan [Member]	Dec. 31, 2010 1992 Plan [Member]	Dec. 31, 2009 1992 Plan [Member]	Dec. 31, 2012 Director Plan [Member]	Dec. 31, 2011 Director Plan [Member]	Dec. 31, 2010 Director Plan [Member]	Dec. 31, 2009 Director Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total authorized shares for plan issuance		2,000,000
Number of additional shares autorized for issuance	500,000
Shares available for issuance		326,221																				8,000,000				200,000
Awards granted							190,000	329,160	[1]	37,500	[2]	32,500	[3]	310,000				90,000	310,000		100,000
Vesting period								5 years							5 years	3 years	10 years			5 years
Expiration period		10 years
Value of common stock for each restricted stock unit		1
Weighted average recognition period		1 year 3 months 24 days
Remaining contractual life																										1 year 2 months 12 days
Weighted Average Exercise Per Share, Outstanding																							$ 15.37	$ 9.84	$ 9.75	$ 17.25	$ 17.25	$ 17.25	$ 17.25
Number of Shares, Outstanding			206,674	48,261	111,758	242,277																	5,905	307,129	608,564	70,000	100,000	100,000	100,000

[1] The distribution date of vested restricted stock units is February 18, 2019 for 3,000 restricted stock units and February 19, 2020 for 16,160 restricted stock units.  For 310,000 restricted stock units, the vested restricted stock units will be distributed in equal installments on December 31, 2022, 2023, 2024, 2025 and 2026.

[2] The distribution date of vested restricted stock units is February 22, 2018 for 5,000 restricted stock units and February 18, 2019 for 32,500 restricted stock units.

[3] The distribution date of vested restricted stock units is February 22, 2017.