Debt - Line of Credit (Details) (USD $)	12 Months Ended					12 Months Ended								0 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2013 Credit Agreement [Member]	Dec. 31, 2013 Credit Agreement [Member] Refinancing of Debt [Member]	Dec. 31, 2013 Credit Agreement [Member] Minimum [Member]	Dec. 31, 2013 Credit Agreement [Member] Maximum [Member]	Dec. 31, 2013 Credit Agreement [Member] Adjusted Base Rate Advances [Member] Adjusted Base Rate [Member] Federal Funds Rate [Member] Minimum [Member] Refinancing of Debt [Member]	Dec. 31, 2013 Credit Agreement [Member] Adjusted Base Rate Advances [Member] Adjusted Base Rate [Member] Eurodollar Rate [Member] Minimum [Member] Refinancing of Debt [Member]	Dec. 31, 2013 Credit Agreement [Member] Adjusted Base Rate Advances [Member] Applicable Margin [Member] Minimum [Member] Refinancing of Debt [Member]	Dec. 31, 2013 Credit Agreement [Member] Adjusted Base Rate Advances [Member] Applicable Margin [Member] Maximum [Member] Refinancing of Debt [Member]	Dec. 31, 2013 Credit Agreement [Member] Eurodollar Advances [Member] Applicable Margin [Member] Minimum [Member] Refinancing of Debt [Member]	Dec. 31, 2013 Letter of Credit [Member] Eurodollar Advances [Member] Applicable Margin [Member] Maximum [Member] Refinancing of Debt [Member]	Jan. 06, 2012 Credit Agreement 2012 [Member] Refinancing of Debt [Member]
Line of Credit Facility [Line Items]
Line of Credit Facility, Contractual Term														5 years
Line of Credit Facility, Maximum Borrowing Capacity				$ 300,000,000
Line of Credit Facility, Commitment Fee Percentage						0.175%	0.35%
Line of Credit Facility, Amount Outstanding	0	94,000,000
Line of Credit Facility, Remaining Borrowing Capacity				300,000,000
Line of Credit Facility, Available Additional Borrowing Capacity					200,000,000
Line of Credit, Description Of Variable Rate Basis				LIBOR
Line of Credit Facility, Basis Spread on Variable Rate								0.50%	1.00%	0.125%	0.75%	1.125%	1.75%
Interest Paid	$ 2,100,000	$ 4,300,000	$ 1,100,000