Goodwill and Intangible Assets Goodwill (Details) $ in Thousands	12 Months Ended
	Dec. 31, 2015 USD ($) reportingunits	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2015 USD ($)
Goodwill [Roll Forward]
Balance at beginning of year	$ 530,593	$ 530,607	$ 530,656
Other goodwill deductions	0	(14)	(49)
Balance at end of year	530,593	530,593	530,607
Goodwill	530,593	$ 530,607	$ 530,656	$ 530,593
Subsidiaries | One Reporting Unit
Goodwill [Roll Forward]
Balance at end of year	$ 167,500
Number of reporting units | reportingunits	1
Goodwill	$ 167,500			$ 167,500
Goodwill impairment test fair value exceeding adjusted net book value				5.00%
Subsidiaries | Six Reporting Units
Goodwill [Roll Forward]
Balance at end of year	$ 363,100
Number of reporting units | reportingunits	6
Goodwill	$ 363,100			$ 363,100
Goodwill impairment test fair value exceeding adjusted net book value				51.00%