Long Term Incentive Plans - Additional Information (Detail) - USD ($) $ in Thousands	3 Months Ended				6 Months Ended				12 Months Ended
	Jun. 30, 2016		Jun. 30, 2015		Jun. 30, 2016		Jun. 30, 2015		Dec. 31, 2014	Mar. 31, 2016	Dec. 31, 2015	Mar. 31, 2015
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense for unit awards					$ 820		$ 547
2014 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Long-Term Incentive Plan, common units permitted for grant									1,500,000
Long-Term Incentive Plan, common units increase per year									100,000
Long-Term Incentive Plan, common units to be issued upon vesting and exercise	110,090				110,090
Long-Term Incentive Plan, common units to issued					14,455
Long-Term Incentive Plan, common units available for future issuance	1,375,455				1,375,455
Long-Term Incentive Plan, common units increased for issuance during the period					0
2004 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Long-Term Incentive Plan, common units to be issued upon vesting and exercise	194,820				194,820
Long-Term Incentive Plan, common units to issued					626,188
Long-Term Incentive Plan, common units available for future issuance	0				0
Unit appreciation rights
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense for unit awards	$ 100		$ 100		$ 100		$ 100
UARs granted under LTIP, contractual term					5 years
UARs vesting period					48 months
UARs granted under LTIP, outstanding	66,793	[1]	87,021	[1]	66,793	[1]	87,021	[1]	123,000	66,793	66,793	112,346
Unrecognized compensation cost related to non-vested UARs	$ 100				$ 100
Common units issued as a result of UARs exercise	0		3,416		0		4,564
Unit appreciation rights | vesting within the following 12 months
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
UARs vesting period					12 months
UARs granted under LTIP, outstanding	16,302				16,302
Restricted phantom units
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
Total compensation expense for unit awards	$ 200		$ 200		$ 400		$ 500
Restricted phantom units | 2014 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
UARs granted under LTIP, outstanding	110,090	[2]	6,281	[2]	110,090	[2]	6,281	[2]	2,189	105,167	102,661	4,241
Restricted phantom units | 2004 Plan
Share-based Compensation Arrangement by Share-based Payment Award [Line Items]
UARs granted under LTIP, outstanding	194,085	[3]	176,349	[3]	194,085	[3]	176,349	[3]	169,122	188,948	184,457	172,793

[1] Based on the closing price of the common units on June 30, 2016, the estimated intrinsic value of the outstanding unit awards was $0.1 million at June 30, 2016. The weighted average remaining contractual life for outstanding UAR awards at June 30, 2016 was 2.1 years.

[2] Based on the closing price of the common units on June 30, 2016, the estimated intrinsic value of the outstanding unit awards was $2.8 million at June 30, 2016.

[3] Based on the closing price of the common units on June 30, 2016, the estimated intrinsic value of the outstanding unit awards was $4.9 million at June 30, 2016.