Share and Unit-based Plans: (Tables)

12 Months Ended

Dec. 31, 2012

Share and Unit-based Plans:

Summary of activity of non-vested stock awards

	2012					2011					2010
	Shares			Weighted Average Grant Date Fair Value		Shares			Weighted Average Grant Date Fair Value		Shares			Weighted Average Grant Date Fair Value
Balance at beginning of year		21,130		$	40.68		63,351		$	53.69		126,137		$	69.53
Granted		9,639			54.43		11,350			48.47		11,664			38.58
Vested		(9,845	)		35.69		(53,571	)		57.36		(74,143	)		78.48
Forfeited		—			—		—			—		(307	)		61.17
Balance at end of year		20,924		$	49.36		21,130		$	40.68		63,351		$	53.69

Summary of activity of non-vested stock units

	2012					2011					2010
	Units			Weighted Average Grant Date Fair Value		Units			Weighted Average Grant Date Fair Value		Units			Weighted Average Grant Date Fair Value
Balance at beginning of year		576,340		$	11.71		1,038,549		$	7.17		1,567,597		$	7.17
Granted		72,322			54.43		64,463			48.36		—			—
Vested		(533,985	)		8.80		(519,272	)		7.17		(529,048	)		7.17
Forfeited		—			—		(7,400	)		12.35		—			—
Balance at end of year		114,677		$	52.19		576,340		$	11.71		1,038,549		$	7.17

Summary of activity of SARs awards

	2012					2011					2010
	Units			Weighted Average Exercise Price		Units			Weighted Average Exercise Price		Units			Weighted Average Exercise Price
Balance at beginning of year		1,156,985		$	56.55		1,242,314		$	56.56		1,324,700		$	56.56
Granted		39,932			59.57		—			—		—			—
Exercised		(32,732	)		56.63		—			—		—			—
Forfeited		—			—		(85,329	)		56.63		(82,386	)		56.63
Balance at end of year		1,164,185		$	56.65		1,156,985		$	56.55		1,242,314		$	56.56

Summary of activity of non-vested LTIP Units

	2012					2011					2010
	Units			Weighted Average Grant Date Fair Value		Units			Weighted Average Grant Date Fair Value		Units			Weighted Average Grant Date Fair Value
Balance at beginning of year		190,000		$	43.30		272,226		$	50.68		252,940		$	55.50
Granted		315,000			40.53		422,631			46.48		232,632			48.89
Vested		(305,000	)		44.85		(504,857	)		49.85		(213,346	)		54.45
Forfeited		—			—		—			—		—			—
Balance at end of year		200,000		$	38.63		190,000		$	43.30		272,226		$	50.68

Summary of activity of stock options

	2012				2011					2010
	Options		Weighted Average Exercise Price		Options			Weighted Average Exercise Price		Options		Weighted Average Exercise Price
Balance at beginning of year		2,700	$	36.51		110,711		$	75.08		110,711	$	75.08
Granted		10,068		59.57		—			—		—		—
Exercised		—		—		—			—		—		—
Forfeited		—		—		(108,011	)		76.05		—		—
Balance at end of year		12,768	$	54.69		2,700		$	36.51		110,711	$	75.08

Summary of activity of non-vested phantom stock units

	2012					2011					2010
	Units			Weighted Average Grant Date Fair Value		Units			Weighted Average Grant Date Fair Value		Units			Weighted Average Grant Date Fair Value
Balance at beginning of year		15,745		$	34.84		29,783		$	34.18		—		$	—
Granted		7,896			57.29		10,534			48.51		54,602			35.33
Vested		(22,179	)		45.24		(24,572	)		39.89		(24,819	)		36.72
Forfeited		(1,462	)		33.74		—			—		—			—
Balance at end of year		—		$	—		15,745		$	34.84		29,783		$	34.18

Compensation cost under the share and unit-based plans

	2012		2011		2010
Stock awards	$	598	$	749	$	3,086
Stock units		3,379		7,526		8,048
LTIP units		9,436		8,955		12,780
SARs		583		626		2,318
Stock options		21		—		402
Phantom stock units		953		980		911
	$	14,970	$	18,836	$	27,545