Significant Service Providers (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015	Dec. 31, 2015
Concentration Risk [Line Items]
Trade accounts receivable	$ 28,734		$ 28,734		$ 21,348
Service Provider Concentration Risk | Revenue | 10 Largest Service Providers
Concentration Risk [Line Items]
Concentration risk percentage	60.30%	63.70%	60.50%	63.70%
Service Provider Concentration Risk | Revenue | Minimum | 1 Service Provider
Concentration Risk [Line Items]
Concentration risk percentage			10.00%	15.00%
Service Provider Concentration Risk | Revenue | Minimum | Service Provider B
Concentration Risk [Line Items]
Concentration risk percentage	10.00%	15.00%
Service Provider Concentration Risk | Revenue | Maximum | 1 Service Provider
Concentration Risk [Line Items]
Concentration risk percentage			15.00%	20.00%
Service Provider Concentration Risk | Revenue | Maximum | Service Provider B
Concentration Risk [Line Items]
Concentration risk percentage	15.00%	20.00%
Service Provider Concentration Risk | Trade Accounts Receivable | Service Provider A
Concentration Risk [Line Items]
Trade accounts receivable	$ 2,900		$ 2,900		3,100
Service Provider Concentration Risk | Trade Accounts Receivable | Service Provider B
Concentration Risk [Line Items]
Trade accounts receivable	$ 2,900		$ 2,900		$ 2,700