Stock and Other Incentive Plans (Details Textual) (USD $)	12 Months Ended																	3 Months Ended				12 Months Ended			3 Months Ended	12 Months Ended				0 Months Ended		12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Restricted Stock and Performance Based Awards [Member]	Dec. 31, 2012 Restricted Stock and Performance Based Awards [Member]	Dec. 31, 2011 Restricted Stock and Performance Based Awards [Member]	Dec. 31, 2013 Stock Incentive Plan [Member]	Dec. 31, 2012 Stock Incentive Plan [Member]	Dec. 31, 2011 Stock Incentive Plan [Member]	Dec. 31, 2013 Stock Incentive Plan [Member] Director [Member]	Dec. 31, 2012 Stock Incentive Plan [Member] Director [Member]	Dec. 31, 2011 Stock Incentive Plan [Member] Director [Member]	Dec. 31, 2013 Stock Incentive Plan [Member] Restricted Stock [Member]	Dec. 31, 2012 Stock Incentive Plan [Member] Restricted Stock [Member]	Dec. 31, 2011 Stock Incentive Plan [Member] Restricted Stock [Member]	Dec. 31, 2013 Stock Incentive Plan [Member] Restricted Stock [Member] Minimum [Member]	Dec. 31, 2013 Stock Incentive Plan [Member] Restricted Stock [Member] Maximum [Member]	Dec. 31, 2012 Stock Incentive Plan [Member] Performance Shares [Member]	Dec. 31, 2012 Stock Incentive Plan [Member] Performance Shares [Member] Minimum [Member]	Dec. 31, 2012 Stock Incentive Plan [Member] Performance Shares [Member] Maximum [Member]	Dec. 31, 2012 Stock Incentive Plan [Member] Performance Shares [Member] Weighted Average [Member]	Dec. 31, 2013 Stock Incentive Plan [Member] Restricted Stock and Performance Based Awards [Member]	Dec. 31, 2013 Stock Incentive Plan [Member] Restricted Stock and Performance Based Awards [Member] Minimum [Member]	Dec. 31, 2013 Stock Incentive Plan [Member] Restricted Stock and Performance Based Awards [Member] Maximum [Member]	Dec. 31, 2013 Executive Incentive Program [Member] Performance Shares [Member]	Dec. 31, 2012 Executive Incentive Program [Member] Performance Shares [Member]	Dec. 31, 2013 Executive Incentive Program [Member] Performance Shares [Member] Executive Officer [Member] executive_officer	Dec. 31, 2012 Executive Incentive Program [Member] Performance Shares [Member] Executive Officer [Member] executive_officer	Dec. 31, 2013 Executive Incentive Program [Member] Performance Shares [Member] Senior Vice President [Member] executive_officer	Jul. 31, 2012 Executive Incentive Program [Member] Performance Shares [Member] Minimum [Member]	Jul. 31, 2012 Executive Incentive Program [Member] Performance Shares [Member] Maximum [Member]	Dec. 31, 2013 Salary Deferral Plan [Member]	Dec. 31, 2012 Salary Deferral Plan [Member]	Dec. 31, 2011 Salary Deferral Plan [Member]	Dec. 31, 2013 Dividend Reinvestment Plan [Member]	Dec. 31, 2012 Dividend Reinvestment Plan [Member]	Dec. 31, 2011 Dividend Reinvestment Plan [Member]	Dec. 31, 2013 Employees Stock Purchase Plan [Member]	Dec. 31, 2012 Employees Stock Purchase Plan [Member]	Dec. 31, 2011 Employees Stock Purchase Plan [Member]	Dec. 31, 2013 Deferral Option One [Member]	Dec. 31, 2013 Deferral Option One [Member] Salary Deferral Plan [Member]	Dec. 31, 2013 Deferral Option Two [Member]	Dec. 31, 2013 Deferral Option Two [Member] Salary Deferral Plan [Member]	Dec. 31, 2013 Deferral Option Three [Member]	Dec. 31, 2013 Deferral Option Three [Member] Salary Deferral Plan [Member]
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Authorization of common shares to issue							2,390,272																												1,000,000
Common shares issued, net of forfeitures							1,693,266	1,576,632	1,182,074
Number of shares authorized							697,006	813,640	1,208,198																													142,367	169,099	232,218
Award vesting period										3 years						3 years	8 years		3 years	8 years	6 years		3 years	8 years	3 years	3 years																3 years		5 years		8 years
Share-based Compensation Arrangement by Share-based Payment Award, Maximum Employee Subscription Rate																																50.00%
Salary Deferral Plan Employer Matching Contribution Percent of Match																																									30.00%		50.00%		100.00%
Share-based compensation expense										$ 600,000	$ 600,000	$ 500,000	$ 4,300,000	$ 2,500,000	$ 2,200,000
Shareholder return performance period used to measure award																														1 year	3 years
Number of executive officers granted awards																											5	5	6
Granted in period																									1,000,000	2,700,000
Granted in period (in shares)				134,752	397,917	106,569																			47,709	112,132
Value of performance based awards released																		3,600,000
401(k) Plan [Abstract]
Percentage of matching contribution	3.00%
Value of matching contribution	400,000	400,000	400,000
Weighted average amortization period remaining																						4 years 8 months 12 days
Shares issued under the plan										20,256	27,864	27,400						154,696														66,787	89,421	52,905
Withheld of common stock													18,118	3,359	4,576
Number of restricted shares vested upon the retirement of a member of the board of directors				116,645	58,531	44,211
Total DRIP shares issued under the Plan																																			519,465
Total shares issued under the Dividend Reinvestment Plan																																			16,422	16,732	18,791
Value of shares available for grant each year																																						25,000
Discount on market price on the date of grant	85.00%																																					85.00%
Discount on market price on the date of exercise	85.00%																																					85.00%
Option expiration period																																						27 months
Cash received from employees upon exercising options																																						$ 1,300,000	$ 1,000,000	$ 200,000