Slicers (applies to each fact value in each table cell)

Reporting Entity [Axis]

0001299033 (http://www.sec.gov/CIK)

Debt Disclosure [Abstract]	Period [Axis]
	2015-01-01 - 2015-12-31
Debt Disclosure [Abstract]
Summary of long-term debt	The table below summarizes the debt balance at December 31, 2015 and 2014: (in thousands) 2015   2014 Senior unsecured notes:       6.52% notes due July 15, 2017                                                               $ 22,100   $ 22,100 6.67% notes due July 15, 2019                                                               23,855   23,855      Total long-term debt                                                               $ 45,955   $ 45,955
Aggregate contractual annual maturities for long-term debt	The table below summarizes the aggregate contractual annual maturities for the total debt balance at December 31, 2015: (in thousands) Contractual Maturities 2016 $ — 2017 22,100 2018 — 2019 23,855 2020 — Thereafter                                                               —     Total long-term debt                                                  $ 45,955