Debt Interest Expense and Other Debt Information (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Debt Instrument [Line Items]
Interest expense, debt			$ 27,978	$ 28,594
Less capitalized interest			(668)	(1,226)
Interest expense	$ 9,486	$ 8,585	27,310	27,368
Cash paid for interest			31,165	35,627
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Interest expense, debt			11,447	9,717
Senior Notes [Member] | 6.5% Senior Notes [Member]
Debt Instrument [Line Items]
Interest expense, debt			14,631	14,571
Senior Notes [Member] | 8.25% Senior Notes [Member]
Debt Instrument [Line Items]
Interest expense, debt			0	2,544
Amortization discount and deferred debt issuance costs [Member]
Debt Instrument [Line Items]
Interest expense, debt			1,425	1,384
Loan Lending Commitment Arrangement Fees [Member]
Debt Instrument [Line Items]
Interest expense, debt			$ 475	$ 378