Fair Value Measurements (Narrative) (Details) (USD $)	Sep. 30, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Line of credit facility, amount outstanding	$ 30,800,000	$ 0
6.625% senior subordinated notes due 2021, net of unamortized discount of $4.0 million at September 30, 2014 and $4.3 million at December 31, 2013	646,043,000	645,696,000
Level 2 [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Estimated fair value of long-term debt	$ 655,800,000	$ 688,200,000