Stock Compensation Plans (Details 1) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
1998 Long-Term Incentive Plan [Member]
Summary of changes in options outstanding
Number of Shares outstanding, Beginning balance (in shares)	169,051	413,710	720,791
Weighted Average Exercise Price outstanding, Beginning balance (in dollars per share)	$ 21.82	$ 19.88	$ 18.19
Number of Shares outstanding, Granted (in shares)	0	0	0
Weighted Average Exercise Price outstanding, Granted (in dollars per share)	$ 0	$ 0	$ 0
Number of Shares outstanding, Exercised (in shares)	(165,401)	(243,659)	(306,548)
Weighted Average Exercise Price outstanding, Exercised (in dollars per share)	$ 21.80	$ 18.54	$ 15.93
Number of Shares outstanding, Forfeited (in shares)		0	0
Weighted Average Exercise Price outstanding, Forfeited (in dollars per share)		$ 0	$ 0
Number of Shares outstanding, Expired (in shares)	(3,650)	(1,000)	(533)
Weighted Average Exercise Price outstanding, Expired (in dollars per share)	$ 22.57	$ 14.79	$ 4.76
Number of Shares outstanding, Ending balance (in shares)	0	169,051	413,710
Weighted Average Exercise Price outstanding, Ending balance (in dollars per share)		$ 21.82	$ 19.88
Number of Shares Exercisable, Ending balance (in shares)		169,051	413,710
Weighted Average Exercise Price Exercisable, Ending balance (in dollars per share)		$ 21.82	$ 19.88
2006 Long-Term Incentive Plan [Member]
Summary of changes in options outstanding
Number of Shares outstanding, Beginning balance (in shares)	1,189,012	1,389,598	1,060,057
Weighted Average Exercise Price outstanding, Beginning balance (in dollars per share)	$ 22.91	$ 23.02	$ 22.89
Number of Shares outstanding, Granted (in shares)	0	0	390,750
Weighted Average Exercise Price outstanding, Granted (in dollars per share)	$ 0	$ 0	$ 23.24
Number of Shares outstanding, Exercised (in shares)	(297,528)	(170,998)	(29,862)
Weighted Average Exercise Price outstanding, Exercised (in dollars per share)	$ 23.11	$ 24.04	$ 21.62
Number of Shares outstanding, Forfeited (in shares)	(3,125)	(20,087)	(22,722)
Weighted Average Exercise Price outstanding, Forfeited (in dollars per share)	$ 23.24	$ 20.48	$ 19.92
Number of Shares outstanding, Expired (in shares)	(5,250)	(9,501)	(8,625)
Weighted Average Exercise Price outstanding, Expired (in dollars per share)	$ 23.89	$ 23.64	$ 29.62
Number of Shares outstanding, Ending balance (in shares)	883,109	1,189,012	1,389,598
Weighted Average Exercise Price outstanding, Ending balance (in dollars per share)	$ 22.84	$ 22.91	$ 23.02
Number of Shares Exercisable, Ending balance (in shares)	781,574	885,003	754,622
Weighted Average Exercise Price Exercisable, Ending balance (in dollars per share)	$ 22.79	$ 23.67	$ 24.86
2010 Long-Term Incentive Plan [Member]
Summary of changes in options outstanding
Number of Shares outstanding, Beginning balance (in shares)	356,050
Weighted Average Exercise Price outstanding, Beginning balance (in dollars per share)	$ 30.66	$ 0
Number of Shares outstanding, Granted (in shares)	417,420	379,425
Weighted Average Exercise Price outstanding, Granted (in dollars per share)	$ 29.80	$ 30.66
Number of Shares outstanding, Exercised (in shares)	(567)	0
Weighted Average Exercise Price outstanding, Exercised (in dollars per share)	$ 30.66	$ 0
Number of Shares outstanding, Forfeited (in shares)	(22,107)	(23,375)
Weighted Average Exercise Price outstanding, Forfeited (in dollars per share)	$ 30.12	$ 30.66
Number of Shares outstanding, Expired (in shares)	(500)	0
Weighted Average Exercise Price outstanding, Expired (in dollars per share)	$ 30.66	$ 0
Number of Shares outstanding, Ending balance (in shares)	750,296	356,050
Weighted Average Exercise Price outstanding, Ending balance (in dollars per share)	$ 30.20	$ 30.66
Number of Shares Exercisable, Ending balance (in shares)	117,219	0
Weighted Average Exercise Price Exercisable, Ending balance (in dollars per share)	$ 30.66	$ 0