Share-Based Compensation and Equity - Share-based Compensation Expense (Details) (USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Pre-tax compensation expense	$ 14,932	$ 13,840	$ 14,296
Tax benefit	(5,066)	(4,644)	(4,912)
Compensation expense, net of tax	9,866	9,196	9,384
Stock Options [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Pre-tax compensation expense	6,032	2,572	3,486
Tax benefit	(2,198)	(825)	(1,238)
Compensation expense, net of tax	3,834	1,747	2,248
Restricted Stock Units [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Pre-tax compensation expense	5,580	5,741	5,734
Tax benefit	(1,672)	(1,809)	(1,845)
Compensation expense, net of tax	3,908	3,932	3,889
Performance Shares [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Pre-tax compensation expense	2,162	4,425	4,076
Tax benefit	(768)	(1,602)	(1,459)
Compensation expense, net of tax	1,394	2,823	2,617
Director Deferred Shares [Member]
Employee Service Share-based Compensation, Allocation of Recognized Period Costs [Line Items]
Pre-tax compensation expense	1,158	1,102	1,000
Tax benefit	(428)	(408)	(370)
Compensation expense, net of tax	$ 730	$ 694	$ 630