Revolving Credit Facility - Narrative (Details) - Revolving Credit Facility - August 2010 Credit Facility Agreement	Aug. 02, 2010 USD ($)	Dec. 31, 2015 USD ($)
Line of Credit Facility [Line Items]
Maximum borrowing capacity on line of credit	$ 175,000,000
Increase to borrowing capacity	$ 50,000,000
Unused capacity		$ 54,300,000
Borrowings to be drawn		$ 700,000
Minimum interest coverage ratio	5
Minimum | Eurodollar
Line of Credit Facility [Line Items]
Additional basis on borrowings	1.25%
Minimum | Base Rate
Line of Credit Facility [Line Items]
Additional basis on borrowings	0.25%
Maximum | Eurodollar
Line of Credit Facility [Line Items]
Additional basis on borrowings	2.50%
Maximum | Base Rate
Line of Credit Facility [Line Items]
Additional basis on borrowings	1.50%
Quarter ending December 31, 2015 and thereafter
Line of Credit Facility [Line Items]
Maximum leverage ratio	3.0