Debt Additional Disclosures (Details) $ in Thousands	Feb. 05, 2016 USD ($) Rate	May 02, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Jul. 19, 2016 USD ($) Rate	May 30, 2014 USD ($)
Secured Debt [Member] | Senior Debt Obligations [Member]
Long-Term Debt Additional Disclosures [Line Items]
Pledged Financial Instruments, Not Separately Reported, Securities for Letter of Credit Facilities			$ 4,782
SunTrust Bank [Member] | Revolving Credit Facility [Member]
Long-Term Debt Additional Disclosures [Line Items]
Revolving credit facility with SunTrust			20,000	$ 10,000
Line of Credit Facility, Current Borrowing Capacity	$ 250,000					$ 150,000
Line of Credit Facility, Maximum Borrowing Capacity	$ 150,000					$ 75,000
Total Net Debt Ratio, Maximum	3.50
Total Net Debt Ratio, Minimum	1.50
EBITDA Ratio, Maximum	1.00
EBITDA Ratio, Minimum	1.00
Total Net Debt Ratio, Default	2.75
EBITDA Ratio, Default	1.00
Aggregate Revolving Commitment Percentage | Rate	10.00%
SunTrust Bank [Member] | Revolving Credit Facility [Member] | Second Amended Credit Facility [Member]
Long-Term Debt Additional Disclosures [Line Items]
Term Loan, Amount Outstanding, Current			7,500
Term Loan, Amount Outstanding, Noncurrent			103,750
Line of Credit Facility, Current Borrowing Capacity					$ 450,000
Long-term Line of Credit					300,000
Term Loan, Borrowing Capacity					$ 150,000
Line of Credit Facility, Interest Rate at Period End | Rate					5.00%
Term Loan and Line of Credit Facility, Amount Outstanding			131,250
Term loan with SunTrust			$ 111,250	$ 113,125
SunTrust Bank [Member] | Revolving Credit Facility [Member] | Subsequent Event [Member] | Second Amended Credit Facility [Member]
Long-Term Debt Additional Disclosures [Line Items]
Term loan with SunTrust		$ 111,250
SunTrust Bank [Member] | Revolving Credit Facility [Member] | Minimum [Member]
Long-Term Debt Additional Disclosures [Line Items]
Line of Credit Facility, Interest Rate, Additional Margin | Rate	0.75%
Line of Credit Facility, Interest Rate, LIBOR | Rate	1.75%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage | Rate	0.30%
SunTrust Bank [Member] | Revolving Credit Facility [Member] | Maximum [Member]
Long-Term Debt Additional Disclosures [Line Items]
Line of Credit Facility, Interest Rate, Additional Margin | Rate	1.75%
Line of Credit Facility, Interest Rate, LIBOR | Rate	2.75%
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage | Rate	0.50%