Debt - Narrative (Details) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2013 Line of Credit, Current Facility [Member]	Jun. 30, 2013 Line of Credit, Previous Facility [Member]	Dec. 31, 2012 Line of Credit, Previous Facility [Member]
Debt Instrument [Line Items]
Line of Credit Facility Current Borrowing Capacity	$ 300,000	$ 175,000
Line of Credit Facility Maximum Borrowing Capacity	400,000
Line Of Credit Maturity Date	2018-06
Line of Credit Facility, Covenant Terms	In addition, the revised facility amends certain financial, acquisition and other covenants, but the consolidated leverage ratio calculation, for which access to credit under the former facility largely depended upon, remains relatively consistent and cannot exceed 3.50 to 1.
Line of Credit Facility, Covenant Compliance	the consolidated leverage ratio was below 1.0 to 1 and the Company was also in compliance with all of the other covenants.
Line of Credit Facility, Amount Outstanding	$ 5,000		$ 12,200