Schedule II: Valuation and Qualifying accounts (Details) (Allowance for Doubtful Accounts [Member], USD $) In Thousands, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Allowance for Doubtful Accounts [Member]
Movement in Valuation Allowances and Reserves [Roll Forward]
Balance at Beginning of Year	$ 2,219	$ 1,039	$ 1,047
Additions: Charged Against Operations	348	1,304	427
Deductions: Uncollectible Accounts Written Off	(574)	(124)	(435)
Balance at End of Year	$ 1,993	$ 2,219	$ 1,039