Long-Term Debt - Additional Information (Details) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Mar. 31, 2017	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Debt Instrument [Line Items]
Deferred financing costs, Net Carrying Amount	$ 570		$ 521
TDC | Senior Secured Notes, 8.50%
Debt Instrument [Line Items]
Long-term debt, face amount			$ 25,000		$ 25,000
Long-term debt, stated interest rate	8.50%		8.50%		8.50%
Deferred financing costs, Net Carrying Amount	$ 100		$ 100
SDTS Credit Agreements | Senior Secured Notes, 5.04%
Debt Instrument [Line Items]
Long-term debt, face amount			$ 60,000	$ 60,000
Long-term debt, stated interest rate	5.04%		5.04%	5.04%
SDTS Credit Agreements | Senior Secured Notes, 7.25%
Debt Instrument [Line Items]
Long-term debt, face amount			$ 53,500			$ 53,500
Long-term debt, stated interest rate	7.25%		7.25%			7.25%
SDTS Credit Agreements | Senior Secured Notes, 6.47%
Debt Instrument [Line Items]
Long-term debt, face amount			$ 110,000		$ 110,000
Long-term debt, stated interest rate	6.47%		6.47%		6.47%
SDTS Credit Agreements | Series A Notes
Debt Instrument [Line Items]
Long-term debt, face amount		$ 400,000
Long-term debt, stated interest rate		3.86%
Long-Term Debt Maturity Period		10 years
SDTS Credit Agreements | Series B Notes
Debt Instrument [Line Items]
Long-term debt, face amount	$ 100,000
Long-term debt, stated interest rate	3.86%
Long-Term Debt Maturity Period	10 years