Capital and Financing Transactions - Schedule of Credit Facilities Outstanding (Details) (USD $)	12 Months Ended			0 Months Ended
	Dec. 31, 2014	Dec. 31, 2013		Jun. 12, 2013	Oct. 01, 2012	Feb. 10, 2012
Line of Credit Facility [Abstract]
Outstanding Balance	$ 481,500,000	$ 303,000,000
Working Capital Revolving Credit Facility
Line of Credit Facility [Abstract]
Interest rate	1.70%
Maturity	Mar. 30, 2018
Outstanding Balance	0
Unsecured Revolving Credit Facility
Line of Credit Facility [Abstract]
Interest rate	1.60%	2.00%
Maturity	Mar. 30, 2018	Mar. 29, 2016
Outstanding Balance	131,500,000	58,000,000
Five-year Term Loan
Line of Credit Facility [Abstract]
Interest rate	2.50%
Maturity	Mar. 29, 2019
Outstanding Balance	250,000,000
Seven-year Term Loan
Line of Credit Facility [Abstract]
Interest rate	4.30%
Maturity	Mar. 31, 2021
Outstanding Balance	100,000,000
Unsecured Working Capital Revolving Credit Facility
Line of Credit Facility [Abstract]
Interest rate		0.00%
Maturity		Mar. 29, 2016
Outstanding Balance		0
Unsecured Term Loan
Line of Credit Facility [Abstract]
Interest rate		2.50%	[1]
Maturity		Sep. 27, 2017	[1]
Outstanding Balance		125,000,000	[1]
Basis spread on variable rate (in percent)				1.45%
Term Loan
Line of Credit Facility [Abstract]
Interest rate		3.30%	[2]
Maturity		Jun. 11, 2018	[2]
Outstanding Balance		120,000,000	[2]
Interest Rate Swap
Line of Credit Facility [Abstract]
Number of interest rate derivatives held					2
Notional amount				120,000,000	$ 125,000,000
Derivative interest rate (in percent)				1.60%	0.70%
Derivative contract term				5 years	5 years
Line of Credit | Unsecured Term Loan
Line of Credit Facility [Abstract]
Period end interest rate (in percent)					2.45%
Line of Credit | Term Loan
Line of Credit Facility [Abstract]
Period end interest rate (in percent)				3.30%
Line of Credit | London Interbank Offered Rate (LIBOR) | Unsecured Term Loan
Line of Credit Facility [Abstract]
Interest rate during the period (in percent)					1.75%
Line of Credit | London Interbank Offered Rate (LIBOR) | Term Loan
Line of Credit Facility [Abstract]
Interest rate during the period (in percent)				1.70%
Minimum
Line of Credit Facility [Abstract]
Basis spread on variable rate (in percent)						2.50%
Minimum | Unsecured Term Loan
Line of Credit Facility [Abstract]
Basis spread on variable rate (in percent)				1.45%
Minimum | Line of Credit | London Interbank Offered Rate (LIBOR) | Unsecured Term Loan
Line of Credit Facility [Abstract]
Basis spread on variable rate (in percent)					1.50%
Minimum | Line of Credit | London Interbank Offered Rate (LIBOR) | Term Loan
Line of Credit Facility [Abstract]
Basis spread on variable rate (in percent)				1.45%
Maximum
Line of Credit Facility [Abstract]
Basis spread on variable rate (in percent)						3.50%
Maximum | Unsecured Term Loan
Line of Credit Facility [Abstract]
Basis spread on variable rate (in percent)				2.00%
Maximum | Line of Credit | London Interbank Offered Rate (LIBOR) | Unsecured Term Loan
Line of Credit Facility [Abstract]
Basis spread on variable rate (in percent)					2.25%
Maximum | Line of Credit | London Interbank Offered Rate (LIBOR) | Term Loan
Line of Credit Facility [Abstract]
Basis spread on variable rate (in percent)				2.20%

[1] Effective October 1, 2012, the Company executed two floating-to-fixed interest rate swaps associated with the Term Loan Facility totaling $125 million, locking LIBOR at 0.7% for five years. The loan bears interest at LIBOR plus the applicable spread which ranges between 150 to 225 basis points based on overall Company leverage. The current spread associated with the loan is 1.75% resulting in an all-in rate of 2.45%.

[2] Effective June 12, 2013, the Company entered into a new floating-to-fixed interest rate swap associated with a New Term Loan Facility totaling $120 million, locking LIBOR at 1.6% for five years. The loan bears interest at LIBOR plus the applicable spread which ranges between 145 to 220 basis points based on overall Company leverage. The current spread associated with the loan is 1.7% resulting in an all-in rate of 3.3%.