Indebtedness (Narrative) (Details) (USD $)	1 Months Ended	3 Months Ended
	May 31, 2014	Mar. 31, 2015	Dec. 31, 2014
Debt Instrument [Line Items]
Line of credit facility, term	5 years
Line of credit, amount outstanding		$ 62,000,000	$ 0
Maximum borrowing capacity	250,000,000
Line of credit facility, accordion feature	150,000,000
Current portion of long-term debt		$ 131,850,000
Debt instrument, public price percentage of par		4.90%
Letter of Credit [Member]
Debt Instrument [Line Items]
Debt instrument, maturity date		May 06, 2019