Agreement of Limited Partnership (Details)		3 Months Ended									12 Months Ended
	Feb. 07, 2018 $ / shares	Mar. 31, 2018 USD ($) $ / shares	Dec. 31, 2017 USD ($) $ / shares	Sep. 30, 2017 USD ($) $ / shares	Jun. 30, 2017 USD ($) $ / shares	Mar. 31, 2017 USD ($) $ / shares	Dec. 31, 2016 USD ($) $ / shares	Sep. 30, 2016 USD ($) $ / shares	Jun. 30, 2016 USD ($) $ / shares	Mar. 31, 2016 USD ($) $ / shares	Dec. 31, 2017 USD ($) trading_day $ / shares $ / Unit	Dec. 31, 2016 USD ($) $ / shares	Dec. 31, 2015 USD ($) $ / shares
Agreement of limited partnership
Declared and paid partnership distributions											$ 124,600,000	$ 257,500,000	$ 294,800,000
Available cash received from operating partnership (as a percent)											99.00%
Distribution Made to Limited and General Partners, Distributions Declared, Total			$ 33,800,000	$ 42,700,000	$ 19,500,000	$ 28,600,000	$ 49,000,000	$ 78,800,000	$ 39,500,000	$ 90,200,000
Number of average trading days' closing prices used to determine the purchase price of outstanding units of non-affiliates | trading_day											20
Minimum Quarterly Distributions
Agreement of limited partnership
Target Limit (per unit) | $ / Unit											0.605
Target Increment (per unit) | $ / Unit											0.605
Income and distribution allocation (as a percent)											100.00%
Minimum Quarterly Distributions | Maximum
Agreement of limited partnership
Incentive Distribution, Distribution											$ 11.3
First Target
Agreement of limited partnership
Target Limit (per unit) | $ / Unit											0.715
Target Increment (per unit) | $ / Unit											0.110
Income and distribution allocation (as a percent)											100.00%
First Target | Maximum
Agreement of limited partnership
Incentive Distribution, Distribution											$ 13.4
Second Target
Agreement of limited partnership
Target Limit (per unit) | $ / Unit											0.825
Target Increment (per unit) | $ / Unit											0.110
Income and distribution allocation (as a percent)											100.00%
Second Target | Maximum
Agreement of limited partnership
Incentive Distribution, Distribution											$ 15.4
Third Target
Agreement of limited partnership
Target Limit (per unit) | $ / Unit											1.045
Target Increment (per unit) | $ / Unit											0.220
Income and distribution allocation (as a percent)											100.00%
Third Target | Maximum
Agreement of limited partnership
Incentive Distribution, Distribution											$ 19.5
Final Target and Beyond
Agreement of limited partnership
Target Increment (per unit) | $ / Unit											0.000
Income and distribution allocation (as a percent)											100.00%
Final Target and Beyond | Minimum
Agreement of limited partnership
Target Limit (per unit) | $ / Unit											1.045
Incentive Distribution, Distribution											$ 19.5
Common and Class B Common Units
Agreement of limited partnership
Cash distribution made, excluding when cumulative distribution is specified, (as a percent)											99.975%
Common units
Agreement of limited partnership
Declared and paid partnership distributions			$ 25,200,000	$ 29,600,000	$ 17,900,000	$ 22,600,000	$ 32,700,000	$ 47,700,000	$ 28,000,000	$ 53,300,000
Cash distribution declared per common limited partnership unit (in dollars per unit) | $ / shares			$ 1.36	$ 1.60	$ 0.97	$ 1.22	$ 1.77	$ 2.58	$ 1.51	$ 2.88	$ 5.15	$ 8.74	$ 9.75
Common units | Minimum Quarterly Distributions
Agreement of limited partnership
Income and distribution allocation (as a percent)											98.99%
Common units | First Target
Agreement of limited partnership
Income and distribution allocation (as a percent)											98.99%
Common units | Second Target
Agreement of limited partnership
Income and distribution allocation (as a percent)											85.859%
Common units | Third Target
Agreement of limited partnership
Income and distribution allocation (as a percent)											75.758%
Common units | Final Target and Beyond
Agreement of limited partnership
Income and distribution allocation (as a percent)											50.505%
Class B Common Units
Agreement of limited partnership
Declared and paid partnership distributions			$ 300,000	$ 400,000	$ 200,000	$ 300,000	$ 500,000	$ 700,000	$ 400,000	$ 900,000
Cash distribution declared per common limited partnership unit (in dollars per unit) | $ / shares			$ 1.79	$ 2.26	$ 1.04	$ 1.52	$ 2.60	$ 4.17	$ 2.09	$ 4.78	$ 6.61	$ 13.64	$ 15.61
Class B Common Units | Minimum Quarterly Distributions
Agreement of limited partnership
Income and distribution allocation (as a percent)											0.985%
Class B Common Units | First Target
Agreement of limited partnership
Income and distribution allocation (as a percent)											0.985%
Class B Common Units | Second Target
Agreement of limited partnership
Income and distribution allocation (as a percent)											0.985%
Class B Common Units | Third Target
Agreement of limited partnership
Income and distribution allocation (as a percent)											0.985%
Class B Common Units | Final Target and Beyond
Agreement of limited partnership
Income and distribution allocation (as a percent)											0.985%
General Partner's Interest
Agreement of limited partnership
Declared and paid partnership distributions			$ 8,300,000	$ 12,700,000	$ 1,400,000	$ 5,700,000	$ 15,800,000	$ 30,400,000	$ 11,100,000	$ 36,000,000
Available cash distributed from operating partnership to General Partner (as a percent)											1.00%
General Partner Distributions											$ (1,200,000)	$ (2,600,000)	$ (2,900,000)
Cash distribution made, excluding when cumulative distribution is specified, (as a percent)											0.025%
Percentage of outstanding units owned by the General Partner and its affiliates			75.10%								75.10%
General Partner's Interest | Minimum
Agreement of limited partnership
Percentage of ownership of non-affiliates of the General Partner allowing majority owner to acquire outstanding units held by non-affiliated persons											25.00%
General Partner's Interest | Minimum Quarterly Distributions
Agreement of limited partnership
Income and distribution allocation (as a percent)											0.025%
General Partner's Interest | First Target
Agreement of limited partnership
Income and distribution allocation (as a percent)											0.025%
General Partner's Interest | Second Target
Agreement of limited partnership
Income and distribution allocation (as a percent)											13.156%
General Partner's Interest | Third Target
Agreement of limited partnership
Income and distribution allocation (as a percent)											23.257%
General Partner's Interest | Final Target and Beyond
Agreement of limited partnership
Income and distribution allocation (as a percent)											48.51%
Subsequent Event
Agreement of limited partnership
Cash distribution declared per common limited partnership unit (in dollars per unit) | $ / shares	$ 2.03
Distribution Made to Limited and General Partners, Distributions Declared, Total		$ 58,600,000
Subsequent Event | Common units
Agreement of limited partnership
Declared and paid partnership distributions		$ 37,600,000
Cash distribution declared per common limited partnership unit (in dollars per unit) | $ / shares		$ 2.03
Subsequent Event | Class B Common Units
Agreement of limited partnership
Declared and paid partnership distributions		$ 600,000
Cash distribution declared per common limited partnership unit (in dollars per unit) | $ / shares		$ 3.10
Subsequent Event | General Partner's Interest
Agreement of limited partnership
Declared and paid partnership distributions		$ 20,400,000
CF Industries Holdings Inc [Member] | Common units
Agreement of limited partnership
Limited Liability Company or Limited Partnership, Members or Limited Partners, Ownership Interest											75.10%
Terra Nitrogen GP Inc [Member] | Terra Nitrogen Company LP [Member] | Subsequent Event
Agreement of limited partnership
Business Acquisition, Share Price | $ / shares	$ 84.033