Debt (Tables)

12 Months Ended

Dec. 31, 2014

Debt Disclosure [Abstract]

Schedule of Long-term Debt Instruments [Table Text Block]

The Company’s long-term debt consists of the following (dollars in thousands):

	2014		2013
$400 million 6.20% Subordinated Debentures due 2042	$	400,000	$	400,000
$400 million 6.75% Junior Subordinated Debentures due 2065	318,732		318,729
$400 million 4.70% Senior Notes due 2023	398,684		398,533
$400 million 5.00% Senior Notes due 2021	398,583		398,362
$400 million 6.45% Senior Notes due 2019	399,669		399,602
$300 million 5.625% Senior Notes due 2017	299,397		299,124
$100 million 4.09% Promissory Note due 2039	99,228		—
Long-term Debt	$	2,314,293	$	2,214,350

Schedule of Maturities of Long-term Debt [Table Text Block]

Future principal payments due on long-term debt as of December 31, 2014, were as follows (dollars in thousands):

2015	$	2,178
2016	2,470
2017	302,573
2018	2,681
2019	402,792
Thereafter	1,606,337
Total	$	2,319,031