Schedule II - Valuation and Qualifying Accounts (Details) (Allowance for Doubtful Accounts [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Period	$ 9,939	$ 10,528	$ 10,154
Charged to Costs and Expenses	206	15	478
Write-off of Doubtful Accounts	128	604	104
Balance at End of Period	$ 10,017	$ 9,939	$ 10,528