Employee Benefit Plans - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Defined contribution plan expense	$ 5.7	$ 4.2	$ 3.9
Defined Benefit Pension Plans
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Expected contribution	19.6
Expect to recognize unrecognized actuarial losses	17.2
Expect to recognize prior service credit\cost	0.4
U.S. Defined Benefit Pension Plans
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Discount rate	3.80%	4.50%
Long-term return on plan assets	7.50%	10.00%	10.00%
Weighted average discount rate used in determining the net periodic cost	4.50%	3.60%	4.20%
U.S. Defined Benefit Pension Plans | CMRT
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Percentage of average annual rate of return		14.00%
Long-term return on plan assets		10.00%	10.00%
U.S. Defined Benefit Pension Plans | CMRT | Level 1 and Level 2
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Percentage of fair value of asset	80.00%	83.00%
Foreign Pension Plan Defined Benefit
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Discount rate	2.50%	3.80%
Long-term return on plan assets	5.00%	5.00%	5.20%
Weighted average discount rate used in determining the net periodic cost	3.80%	3.70%	4.90%
Foreign Pension Plan Defined Benefit | Canada
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Curtailment		7.1
Defined benefit plan, special termination benefits		0.2
Average basis points of long-term rate of return on investment	125
Foreign Pension Plan Defined Benefit | Canada | Equity Securities
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Percentage of plan asset allocation	45.00%
Foreign Pension Plan Defined Benefit | Canada | Fixed Income Funds
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Percentage of plan asset allocation	47.00%
Foreign Pension Plan Defined Benefit | Canada | Other Investments
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Percentage of plan asset allocation	8.00%
Foreign Pension Plan Defined Benefit | Norway | Equity Securities
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Long-term return on plan assets	6.00%
Percentage of plan asset allocation	11.00%
Foreign Pension Plan Defined Benefit | Norway | Fixed Income Funds
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Long-term return on plan assets	4.00%
Percentage of plan asset allocation	79.00%
Foreign Pension Plan Defined Benefit | Norway | Real estate
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Long-term return on plan assets	5.00%
Percentage of plan asset allocation	7.00%
Foreign Pension Plan Defined Benefit | Norway | Money Markets
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Long-term return on plan assets	3.00%
Foreign Pension Plan Defined Benefit | Norway | Level 3 Inputs
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Percentage of plan asset allocation	10.00%
OPEB
Pension Plans Postretirement And Other Employee Benefits [Line Items]
Expected contribution	1.3
Discount rate	3.40%	4.00%
Curtailment		0.1
Expect to recognize prior service credit\cost	$ 2.0
Weighted average discount rate used in determining the net periodic cost	4.00%	3.47%	3.93%