Financial Instruments (Narrative) (Details) (USD $) In Thousands, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Fair value inputs, Level 2 [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	$ 292,065	$ 473,564
6.5% Senior Notes [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	296,579	295,927
6.5% Senior Notes [Member] | Fair value inputs, Level 2 [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	291,000	313,500
8.25% Senior Notes [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	0	148,703
8.25% Senior Notes [Member] | Fair value inputs, Level 2 [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	0	158,250
Carrying Amount [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	297,644	446,444
Interest Rate Swap [Member]
Debt Instrument [Line Items]
Derivative Asset	1,019	1,670
Financial Liabilities Fair Value Disclosure	1,065	1,814
Interest Rate Swap [Member] | Fair value inputs, Level 2 [Member]
Debt Instrument [Line Items]
Derivative Asset	1,019	1,670
Financial Liabilities Fair Value Disclosure	1,065	1,814
Senior Debt Obligations [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	296,579	444,630
Senior Debt Obligations [Member] | Fair value inputs, Level 2 [Member]
Debt Instrument [Line Items]
Financial Liabilities Fair Value Disclosure	$ 291,000	$ 471,750