Basis of Presentation (Narrative) (Details)	Jun. 30, 2011
PLUM CREEK TIMBER CO INC [Member]
Timber and Timberlands, net (acres)	6,700,000
Product conversion facilities owned in the Northwest United States	8
Curtailed product conversion facilities owned in Northwest US	2
Higher and better use timberlands, which are expected to be sold and/or developed, acres	1,000,000
Land Expect To Sell For Recreational Uses In Acres	800,000
Land Expect To Sell For Conservation In Acres	100,000
Land Designated With Development Potential In Acres	100,000
Total acres of non-strategic timberlands	300,000
PLUM CREEK TIMBERLANDS L P [Member]
Timber and Timberlands, net (acres)	6,700,000
Product conversion facilities owned in the Northwest United States	8
Curtailed product conversion facilities owned in Northwest US	2
Higher and better use timberlands, which are expected to be sold and/or developed, acres	1,000,000
Land Expect To Sell For Recreational Uses In Acres	800,000
Land Expect To Sell For Conservation In Acres	100,000
Land Designated With Development Potential In Acres	100,000
Total acres of non-strategic timberlands	300,000