Earnings per Share Earnings per Share (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Earnings Per Share Calculation [Line Items]
Net Income, Including Portion Attributable to Noncontrolling Interest	$ 10,942	$ 15,570	$ 36,047	$ 38,488
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Preferred Dividends	(1,218)	(1,218)	(3,656)	(3,656)
Net income to common shareholders	9,724	14,352	32,391	34,832
Net Income Available to Common Stockholders, Diluted	$ 10,612	$ 15,226	$ 35,097	$ 37,456
Weighted Average Number of Shares Outstanding, Basic	24,669	24,605	24,665	24,551
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Incremental Common Shares Attributable to Stock Options	231	244	200	238
Incremental Common Shares Attributable to Deferred Compensation	154	133	143	147
Weighted Average Number of Shares Outstanding, Diluted	30,139	30,067	30,093	30,021
Earnings Per Share, Basic	$ 0.39	$ 0.58	$ 1.31	$ 1.42
Earnings Per Share, Diluted	$ 0.35	$ 0.51	$ 1.17	$ 1.25
Anti-dilutive stock equivalent awards not included in the calculation of diluted loss per share	896	1,460	1,288	1,443
2017 Convertible Senior Notes [Member]
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Interest on Convertible Debt, Net of Tax	$ 378	$ 372	$ 1,152	$ 1,117
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Incremental Common Shares Attributable to Conversion of Debt Securities	2,416	2,416	2,416	2,416
2018 Convertible Senior Notes [Member]
Dilutive Securities, Effect on Basic Earnings Per Share [Abstract]
Interest on Convertible Debt, Net of Tax	$ 510	$ 502	$ 1,554	$ 1,507
Incremental Weighted Average Shares Attributable to Dilutive Effect [Abstract]
Incremental Common Shares Attributable to Conversion of Debt Securities	2,669	2,669	2,669	2,669