Debt Interest Expense and Other Debt Information (Details) - USD ($) $ in Thousands	3 Months Ended			9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	[1]	Sep. 30, 2016	Sep. 30, 2015
Debt Instrument [Line Items]
Interest expense, debt				$ 36,756	$ 27,978
Less capitalized interest				498	668
Interest expense	$ 14,447	$ 9,486		36,258	27,310	[1]
Cash paid for interest				33,896	31,165
Revolving Credit Facility [Member]
Debt Instrument [Line Items]
Interest expense, debt				13,600	11,447
Senior Notes [Member] | 6.5% Senior Notes [Member]
Debt Instrument [Line Items]
Interest expense, debt				14,632	14,631
Senior Notes [Member] | Six Percent Senior Notes Due Two Thousand Twenty Four [Member] [Member]
Debt Instrument [Line Items]
Interest expense, debt				4,811	0
Amortization discount and deferred debt issuance costs [Member]
Debt Instrument [Line Items]
Interest expense, debt				2,294	1,425
Commitment Fees and Other [Member]
Debt Instrument [Line Items]
Interest expense, debt				$ 1,419	$ 475

[1] Retrospectively adjusted as described in Note 1.