Acquisitions - National Meter (Details) - USD ($) $ in Thousands		6 Months Ended
	Oct. 01, 2014	Jun. 30, 2015	Dec. 31, 2014
Business Acquisition
Goodwill		$ 47,712	$ 47,722
National Meter and Automation, Inc.
Business Acquisition
Percentage acquired	100.00%
Incremental revenue	$ 15,000
Total purchase consideration	22,900
Cash payment	$ 20,300
Deferred payments			2,500
Receivables			3,900
Inventory			4,500
Property, plant and equipment			2,800
Intangibles			9,800
Goodwill			3,000
Current liabilities			100
National Meter and Automation, Inc. | Accounts Payable
Business Acquisition
Deferred payments			2,000
National Meter and Automation, Inc. | Long-term Debt
Business Acquisition
Deferred payments			$ 500
National Meter and Automation, Inc. | Customer relationships
Business Acquisition
Estimated average useful life (in years)		12 years