Supplemental Cash Flow Information (Details) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Summary of additional cash flow information
Interest and related financing fees paid	$ 2,802	$ 3,748
Income taxes paid	906	1,967
Additional Paid-in Capital
Summary of additional cash flow information
Increase in additional paid in capital from issuance of shares - common stock from cashless exercise of stock options		538
CPI | Additional Paid-in Capital
Summary of additional cash flow information
Increase in additional paid in capital from issuance of shares of common stock related to purchase of CPI		$ 618